The mention of the words tumor or cancer cause most people to think of the death of their pet. Despite tremendous progress in the treatment of tumors, most people unfortunately still find their minds drawn into the worst thoughts possible. It is important to know that many tumors of domestic cats can be cured with the pet living normally for years after treatment.

It is first important to understand the language of this branch of medicine as many terms are often used to describe abnormal growths in the body. The words neoplasia or neoplasm are the proper terms used to describe any new and abnormal growth in the body. These words do not describe how "dangerous" a growth may be, only that an abnormal growth does exist. The word tumor is sometimes used instead of the word neoplasm. More correctly, the word tumor describes a swelling of/in a tissue. Oncology is the study of neoplasia or tumors.

The word benign means not malignant, and that the chances for recovery are favorable. It may also be used to describe a neoplasm that is not likely to spread to other parts of the body. The word everyone dreads most is malignant. A malignant tumor is one likely to become worse with time, likely to spread locally or to distant parts of the body, and likely to ultimately lead to death of the cat. These would be the most dangerous types of neoplasms. Cancer is the common term for a malignant neoplasm so this word is commonly used to indicate a severe type of tumor.

Some tumors are classified as pre-malignant meaning that the tumor may be benign now, but is likely to become malignant if more time goes by. These tumors may be removed before they turn into a cancerous growth. Another term commonly used is that of metastasis. This means that a neoplasm has spread from the area or organ where it originated to grow (also) in another organ or area. Once a neoplasm has metastasized it becomes very difficult to treat and will cause more damage to the cat.

Although our ability to diagnose and treat all types of tumors has come a long way in the last decade, we are still far from understanding what actually causes a particular tumor to form. Owners commonly ask, "what caused it?" when the diagnosis of neoplasia is discussed with the veterinarian. Unfortunately, most doctors are left to say that any such growth arose spontaneously, but we just don't know, nor can we ever (yet) be exactly certain why.

It has been determined that radiation, poisons and toxins, viruses, especially feline leukemia, hormones in the male or female, chronic irritations, internal and external parasites, and certain drugs can cause neoplasia. Most importantly, however, genetic factors are probably the single most important reason any individual gets a certain tumor. In other words, our cats all have certain inherited genes, which either help to protect against the development of neoplasia or to some degree increase the chances that certain tumors will form. At best with good preventative care and by avoiding all the things mentioned above which are known to contribute to cancers and tumors, the odds of developing neoplasia can be kept as low as possible.

While tumors can occur at any age, they are most common in cats older than 5 years of age with the exception of tumors in cats positive for the feline leukemia virus. Some tumors are more common in certain breeds (genetics again) and in cats with certain coat colors. Overall the chances any given cat will get any type of tumor are only about 1.5-4.7 cats out of every 1000! Of this rate, about 70% of these cats will have malignant tumors. Skin and soft tissue cancers make up 35-45% of all tumors; tumors of the bloodcells and bone marrow make up another 30-40% of all cancers. The high percentages of blood cell cancers, and the relatively high malignancy percentages seen in cats can be blamed on the FeLV, FIV and Feline Sarcoma Viruses which all can directly produce various cancers in the cat.

In all other sections within this program, diseases are indicated based on clinical signs or symptoms that will usually appear. As neoplastic growths can occur in any tissue or organ, in any part thereof, and even spread to multiple areas, it is impossible to say that any one or general set of clinical signs points to some type of tumor. An important point to remember at all times when discussing neoplasia; tumors do not follow exact or specific patterns, they have tendencies, but we can only predict in general terms what a tumor will do once it begins to grow inside the cat.

External tumors will be the most obvious, appearing as a swelling, sore or evidently irregular growth. Some external growths may ulcerate, discharge or even begin to decay. Signs of internal tumors are often vague and can include pain, gain or loss of appetite, gain or loss of weight, swelling to the abdomen or feet, unusual bleeding, weakness, trouble breathing, constipation or diarrhea, vomiting, changes in gum color, seizures, paralysis, changes in thirst or urinary habits, fever, and a few other symptoms we have probably omitted. With this said, one can see that the diagnosis is often less than obvious.

A veterinarian will use most any of the commonly used tests to help determine if a tumor is present. These include blood analysis, urinalysis, X-rays, ultrasound, cytology, FeLV and FIV testing, and biopsy. Where possible, cytology is an excellent preliminary test for neoplasia. Part of suspected tumors can often be aspirated into a syringe, washed off of an internal surface or scraped free from an area and placed on a slide, stained and examined by the veterinarian under the microscope. While this may not constitute an exact diagnosis, it is easy and inexpensive and will quickly help the veterinarian determine what should be done to best help the cat.

A biopsy, however, is the only sure and accurate way to determine exactly what type of tumor is present and if it is benign or malignant. A biopsy is performed by taking a small section from a suspected tumor and having a veterinary pathologist examine it for an exact determination. A biopsy may be taken before surgery to help the doctor know what he/she is dealing with and how to best attempt a cure, or after all of a mass is removed to find out what is being treated and if more surgery or other therapy will be necessary.

Just as it is nearly impossible to list exact symptoms for the all the various types of tumors that can exist, is difficult to say precisely what treatment(s) or therapy will work best. The most common and most effective type of tumor therapy used on cats is surgery. Up to 50% of all feline tumors can be completely removed and cured with surgery.

Chemotherapy is also available and many cities now have specialists who have the drugs and expertise to provide cats with the most up-to-date therapy available today. Chemotherapy is often the only reasonable coarse for cats with widespread tumors and cancers of the blood and lymphatic systems.

Other types of therapy include cryotherapy or the freezing of tumors, radiation therapy which is available only in limited areas, immunotherapy which employs the use of antibodies and other immune system components to fight tumors, radiosurgery which employs electricity to cut and destroy tumor tissues, and various combinations of all the aforementioned methods. The best treatment will depend on the techniques available, the general health of the patient, the cost involved, the type of neoplasia present and if and where it may have spread, and the skills of the doctors treating the patient.

Adenoma: benign tumor from glandular surface lining tissues.

Adenocarcinoma: malignant growth from glandular tissues.

Carcinoma: malignant tumor from surface lining tissues.

Cyst: benign growth, non-neoplastic and filled with fluid or semi-solid material.

Mass: general term for any lump or growth; may or may not imply neoplasia.

Polyp: any abnormal protrusion from a mucus membrane. (gums, rectum, etc.) ((Polyp))

Sarcoma: tumors from supportive tissues such as blood, bone and muscle.

LEUKEMIA: leukemia defines increased numbers of white blood cells in the circulation with the cells often being types not normally seen. Most all cases of leukemia will involve the bone marrow where blood is produced, but abnormal cells may or may not be seen in the blood. Cats with leukemia will often be weak, have a poor appetite, pale gums, altered consciousness and some type of bleeding problem. Diagnosis is based on blood counts, FeLV and FIV testing and bone marrow biopsy where abnormal types and numbers of cells will be found.

There are several different types of white blood cells in the cat's body. Each of these cells develops from an embryonic precursor in the bone marrow. What this amounts to is that there are many various types of leukemia that can occur, depending on which blood cell and/or juvenile precursor cells become cancerous. All types of leukemia are considered malignant. While an individual discussion of each and every type of leukemia would be impractical, in the next paragraph we will list the names of some types of leukemia your veterinarian may diagnose. These include:

Lymphoblastic and Lymphocytic Leukemias; most common and closely related to other forms of Lymphosarcoma. Other rare forms include Eosinophilic Leukemia, Basophilic Leukemia, Monocytic Leukemia, Acute Undifferentiated Leukemia, Acute or Chronic Myelogenous Leukemia and Mast Cell Leukemia. Many of these cats are positive for feline leukemia.

All types of leukemia may be treatable with various types of chemotherapy and a cure quite possible or at least good long-term survival possible for these patients. The most established types of chemotherapy exist for treatment of these diseases. The only negative would be the costs of this type therapy and the difficulty in treating cats that are FeLV positive.

ERYTHEMIC MYELOSIS aka ERYTHROLEUKEMIA: Erythemic Myelosis is an abnormal proliferation of immature/developing red blood cells. Erythroleukemia entails an abnormal growth of immature red and white blood cells, sort of a mixed-type leukemia. Most cats are FeLV positive. A very serious type of neoplasia.

MEGAKARYOCYTIC LEUKEMIA: occurs when abnormal platelets or their juvenile precursors are in increased numbers in the blood. May be concurrent with other types of leukemia. Usually will not cause much illness by itself but there is no treatment. Quite rare.

SPLENIC NEOPLASIA: most every cancer of the spleen has origin in some other system. This is not to say that cancer cannot be found to arise in the spleen only, but rather, that most splenic tumors are in no way unique to the spleen. Most any tumor that can metastasize can end up in the spleen. These include hemangiosarcoma, mast cell tumors, lymphosarcoma and other various carcinomas. Usually cats will have abdominal enlargement and discomfort. If confined to the spleen, splenectomy can be curative. More widespread neoplasms will require chemotherapy or radiation. ((Hemangiosarcoma of Spleen))

OSTEOSARCOMA: most common bone tumor, highly malignant often having spread before diagnosis can be made. Most often seen in limbs of older cats, these tumors occur much more commonly in dogs. Life may be spared or at least extended with early amputation of limb; chemotherapy or radiation may be helpful. Can be very painful if amputation is not performed. May sometimes cause bones to break spontaneously. An unusual variation known as Parosteal Osteosarcoma can form on the surface of and around the bone. This variation may be curable by surgical removal without the need for amputation. ((Osteosarcoma))

OSTEOMA: uncommon benign relative of osteosarcoma, will rarely spread but may damage bone in the area of the tumor. Will generally grow from surface of the bone. Surgery or amputation may be curative if complete removal is performed.

CHONDROSARCOMA: uncommon tumor of cartilage, malignant but may be removable with surgery and/or radiation therapy. More common in older cats and on the scapula and humerus. Not usually painful and tends to be slow growing. Amputation may still be required.

CHONDROMA: benign tumor of cartilage, quite rare, may still create defects within the bone or joint. More commonly grows on skull or ribs.

FIBROSARCOMA: tumor of connective tissue that can occur in bone, may invade and destroy bony tissue. Relatively common bone tumor. Often mimics osteosarcoma, may not be removable with surgery, (often grows back) but amputation can prove curative.

MULTIPLE MYELOMA: very malignant tumor of bone marrow tissue, usually of antibody producing cells. Will invade the bones, often of the spine, skull, pelvis and ribs, but long bones also may become involved. Causes severe pain, lameness and high blood protein levels, as well as disease in other organs; may be treatable with chemotherapy. see multiple myeloma.

GIANT CELL TUMOR: a very rare tumor, most likely found at the ends of long bones of the hindleg. Can be benign or malignant. Amputation will probably be needed. Little information is available as to the effectiveness of other therapies. Malignant forms will spread wildly, often to the lungs.

EPULIS: a hard, fibrous tumor that arises from periodontal tissues, may be single or multiple and occur along the gums. Some consider this non-neoplastic. A few of these tumors may become calcified and feel like a bone. May be confused with more serious oral tumors and should be removed and biopsied. With surgery and hyperthermia most are cured.

ODONTOMA or ADAMANTINOMA: oral/gingival tumor that originates from dental tissues. Benign but often recurs after surgical removal and can spread along the gums and jaw. Surgical removal, cryotherapy or hyperthermia are all advised.

SQUAMOUS CELL CARCINOMA: relatively common malignant cancer of oral surface tissues, more common to back of mouth. Can attack tongue, tonsils, gums and jawbone, quick to spread deeply in tissues and to lymph nodes. Often ulcerative and can displace teeth. Surgery and radiation can be effective but few cats live longer than 6-9 months after diagnosis. ((SCC))

FIBROSARCOMA: malignant tumor of oral connective tissues. Most common along gums and jaw, invades deeply but slow to spread to distant sites. Can be partly removed with surgery but will most always regrow. Radiation also effective, and another therapy, injections of Acemannen, has been used with some success. Freezing of the tumor has also been used with some success.

SALIVARY ADENOCARCINOMA: malignant tumor of any of the salivary glands, quite rare. Will produce localized swelling and may spread quickly into the neck and mouth. Surgical removal before metastasis can produce a complete cure. Radiation and chemotherapy can be used in advanced cases.

LEIOMYOMA: benign tumor of smooth muscle (the type of muscle in organs), may cause obstruction of the esophagus. Very rare, possibly removable with surgery depending upon location of the tumor.

SQUAMOUS CELL CARCINOMA: malignant cancer of esophageal lining tissues, may be related to oral SCC. Surgery and radiation usually not effective.

FIBROSARCOMA: malignant tumor of connective tissues. Can produce a blockage of the esophagus. May be removable depending on size and location although there would be a limit to how much esophagus could be removed. Usually fatal.

BENIGN ADENOMATOUS POLYPS: pedunculated nodules along stomach lining. Causes no clinical disorder and no treatment is needed. Rare.

LEIOMYOMA: usually solitary tumors of the stomach muscle tissue. Can ulcerate but usually causes no dysfunction nor do they need any treatment in most all cases. Rare.

LEIOMYOSARCOMA: rare cancer of smooth muscle tissue, can involve large portions of the stomach. May be surgically removed if caught early although all or part of the stomach may also need to be removed.

ADENOCARCINOMA: malignant tumor, will often be associated with gastric ulcers; appears as a polyp or firm, solid mass in stomach wall. Will spread to liver, adrenal glands, lungs and regional nodes. Possible to remove by surgically removing part or most of the stomach. Few other treatments are known to be effective.

LYMPHOSARCOMA, GASTRIC see lymphosarcoma

LYMPHOSARCOMA, INTESTINAL see lymphosarcoma

INTESTINAL ADENOCARCINOMA: most common intestinal tumor, very malignant, often leads to intestinal obstruction. May also produce polyploid masses in any location, especially near the rectum. In a few cases where metastasis has not occurred, it may be possible to remove part of the intestine and cure the cat. Most cases, however, have spread through the intestines, lymph nodes and other local tissues by the time a diagnosis is made. Chemotherapy alone or after surgery has also proven of little value. ((Adenocarcinoma))

LEIOMYOMA: usually solitary tumors of the intestinal muscle tissue. Can ulcerate but usually causes obstructions. Can be cured with surgery if obstruction occurs. ((Leiomyoma))

LEIOMYOSARCOMA: rare cancer of smooth muscle tissue, can involve multiple portions of the intestine. Can also result in obstructions. May be surgically removed if caught early although part of the intestines may also need to be removed.

((Intestinal Tumors))

PERIANAL ADENOMA: very rare feline tumor. Tumor forms from glandular tissue in the anus and will grow slowly and progressively, can ulcerate and bleed. Many can be cured with neutering and tumor removal. Freezing, radiation and female hormones have also been used but the first treatment is most always effective.

APOCRINE GLAND CARCINOMA: extremely rare tumor of glandular tissue of anal sacs, uncommon and moderately malignant. May mimic anal sac abscess in appearance. Surgical removal or freezing the best hope of cure. Will spread to lymph nodes and other parts of the digestive system if not treated early.

Tumors or the ear do occur and are similar to any other type of Neoplasia Of The Skin. Diagnosis would be based on skin biopsy. Any nodule of the earflap should be considered neoplastic until proven otherwise. Surgery to remove the lump and/or part of the ear will be needed. Polyps inside the ear canal are common in the cat. ((Polyp))

BETA CELL TUMOR aka INSULINOMA: tumor of insulin producing cells, most always malignant with early metastasis. Can produce excess insulin and cause blood sugar to drop to very low levels causing weakness, seizures and collapse. These symptoms may come and go but diagnosis can be made with blood tests including insulin levels. May be treatable with surgery and chemotherapy, but will often spread to the liver and lymph nodes. Chances for good long-term survival are poor, but these tumors are very uncommon in cats.

THYROID ADENOCARCINOMA aka THYROID CARCINOMA: malignant growth, relatively rare, can grow quite large, sometimes removable surgically. May respond to the use of radiation or chemotherapy.

THYROID ADENOMA: benign tumor, quick to spread from one gland to the other, sometimes to chest and other organs. Often these tumors will secrete excess thyroid hormone and cause hyperthyroid conditions. Cats with increased thyroid hormone production will be restless, have an increased appetite and thirst but will be loosing weight. Surgery can be very successful in curing the problem if caught early. Certain drugs can be used to suppress thyroid hormone production. Radioactive iodine therapy effective but requires specialty care facility. 

ADRENAL GLAND CARCINOMA OR ADENOMA; adenoma is benign, adenocarcinoma likely to spread to liver, lymph nodes, kidneys and lungs. Some will secrete cortisol and produce signs of hyperadrenocorticism. Can be treated with medication that will destroy the adrenal gland or by surgical removal. Prognosis very poor if tumor has metastasized.

PHEOCHROMOCYTOMA: functional adrenal tumor that will produce epinephrine (adrenaline). Very rare, can cause panting, weakness, shock, heart failure, or less serious signs. Difficult to diagnose, often large and malignant. Surgery and chemotherapy may be useful if caught early.

Tumors of the eye are not common with the exception of benign eyelid tumors being seen somewhat frequently. Many can be treated, at least by surgical means, with death from tumors of the eye being very uncommon. Internal eye tumors may require removal of the eye.

DERMOIDS: common tumor of all exposed eye tissues, usually has hairs growing from it which can be irritating. Benign, surgical removal is often curative. Dermoids do occur in other skin areas besides the eye.

CHALAZION: not a tumor but included here as it may be confused as such. Swelling occurs on eyelid due to plugging of glandular duct with possible secondary infection. Can be easily treated with surgery and medication.

MELANOMA: often found inside the eye, but may occur on other structures. Malignant per se, will spread outside the globe if left untreated, often to local node of the head and neck. Removal of the eye is the usual treatment; local removal or freezing may work.

SQUAMOUS CELL CARCINOMA: can occur on eyelids and conjunctiva; more often seen in white or light colored cats. Malignant, but may be responsive to surgery, freezing or radiation if dealt with early. Extreme cases involve deeper areas of the eye-socket.

BASAL CELL CARCINOMA: occurs on eyelids. see..Basal Cell Tumor

LYMPHSARCOMA, OCULAR: most common eye tumor. see..Lymphosarcoma

ADENOMA: most common on the eyelids, can irritate the cornea if it rubs against it; removal by surgery or freezing advised early. For various types see the section on skin tumors.

ADENOCARCINOMA: may be seen on conjunctiva or third eyelid, malignant and can spread to nearby structures. Surgery or freezing advised as soon as possible, third eyelid may need to be removed. For various types see section on skin tumors.

HEMANGIOMA: uncommon tumor most often of the conjunctiva, will bleed if irritated, can be removed completely with surgery.

OVARIAN ADENOCARCINOMA: rare malignant tumor of the ovary. Can be prevented by spaying female cats. Will widely and quickly spread, most cats very old at time of diagnosis. Treatment includes ovariohysterectomy, injections of radioactive material or other chemotherapy.

OVARIAN CYSTADENOMA: uncommon cystic tumor, usually benign. May grow to a moderate size. Possible cure with ovariohysterectomy. Also preventable by spaying.

GERM CELL TUMOR: include dysgerminomas and teratomas, tumors from embryonic-type tissues in the ovaries. Uncommon, can be moderately malignant. Ovariohysterectomy, chemotherapy and radiation will be needed for a cure. Preventable by spaying.

UTERINE ENDOMETRIAL ADENOCARCINOMA: most common uterine tumor, usually occurs in old cats. Will metastasize but will remain inside of the uterine body to make complete removal possible if caught early. Can spread to lungs, heart, abdominal organs and the brain. Preventable by spaying.

UTERINE LEIOMYOMA: the most common uterine tumor, originates from smooth muscle within the uterus, usually benign. Often no outward symptoms will be seen. Ovariohysterectomy can be completely curative. Preventable with spaying except in very rare circumstances. ((Leiomyoma))

UTERINE LEIOMYOSARCOMA: malignant cousin to leiomyoma, will invade and spread inside the abdomen, often before diagnosis. Can cause notable abdominal enlargement among other symptoms. Ovariohysterectomy and chemotherapy poorly effective. Preventable with spaying except in very rare circumstances.

UTERINE FIBROSARCOMA: rare but very invasive malignant cancer, more common in other areas besides the uterus. Can be treated if caught early but often will have invaded other tissues before diagnosis. Ovariohysterectomy and chemotherapy are possible but mostly ineffective. Preventable with spaying except in very rare circumstances.

VAGINAL LEIOMYOMA: the most common vaginal tumor, originates from smooth muscle within the vagina, usually benign but can obstruct the vagina. Often no outward symptoms will be seen. Ovariohysterectomy and surgical removal can be completely curative.

VAGINAL LEIOMYOSARCOMA: malignant cousin to leiomyoma, will invade and spread locally and inside the abdomen, often before diagnosis. Can cause notable mass protruding from vagina, discharge and trouble urinating and defecating. Surgical removal, radiation and chemotherapy all useful but a cure is difficult.

MAMMARY GLAND NEOPLASIA: the third most common type of tumor in female cats comprising as many as 20% of all tumors the queen may have. Can be almost completely prevented by spaying before the first heat as these tumors are highly hormone dependent. Cats spayed after 2.5 years of age have a risk or incident rate 7 times higher than cats spayed before the first cycle. Most tumors occur in cats 9-11 years of age and are found primarily in the breasts closer to the tail.

The mammary glands are highly complex and integrated organs. Breast tumors are not just some simple lump to be dealt with. Because of this complexity, there is no one common presentation for a breast tumor. The masses may be small or very large; round, smooth and encapsulated or irregular and spreading into adjacent tissues. Some are quite benign and harmless; others grow and metastasize rapidly. Some never grow and remain small; others grow so large as to ulcerate and decay as they develop. One breast or multiple glands may be effected, one side of the body or both may have tumors. Drainage may or may not be present. ((Breast Tumor))

As there is such great variability, there is also incredible uncertainty; in other words, you cannot tell by looking which tumors are benign and which are malignant. There is, however, a 75% malignancy rate for these tumors. Understanding this, all cats with any abnormal growth in/on the mammary glands should have the growth or the breast(s) involved surgically removed as soon as possible. This offers the very best chance for both cure and diagnosis.

This is not to say that a complete diagnostic work-up including blood tests, X-rays (to check for metastasis), and aspiration or other forms of biopsy should be neglected. Most cats are older but many can be cured as long as thorough, aggressive care is not postponed. Only cats with confirmed metastasis or severe debilitation should be excluded from surgery. Many malignant tumors can be stopped before they have spread.

Several types of surgery are recommended. For small, solid, well-defined nodules a lumpectomy, or removal of the mass only can be performed. This can be used as a biopsy technique also. For masses that affect only one breast, local mammectomy or removal of one gland alone can be performed. In more extreme cases with large and spreading tumors, several glands, one complete chain of glands (one side) or all glands on both sides can be removed. While some of these may seem to be extreme procedures, the goal is to remove the cancer before it can spread elsewhere in the body. On a few occasions certain lymph nodes should also be removed.

In some cases, chemotherapy, radiation, anti-hormone drugs and immunotherapies have been used, but always to augment surgery. Unfortunately, some tumors will regrow even after the best surgery. Many veterinarians will also advise ovariohysterectomy at the same time as tumor removal, and while there is some debate as to how this effects current or future tumors, this author agrees that there is some good therapeutic value for this procedure being performed.

90% of all breast tumors in cats will be malignant adenocarcinoma, the rest will likely be the more benign adenoma. Pathologic variations that may be encountered include:

MIXED MAMMARY TUMOR: benign.

SIMPLE MAMMARY ADENOMA: benign.

COMPLEX MAMMARY ADENOMA: benign.

FIBROADENOMA: from fibrous tissue, two types, benign.

SOLID MAMMARY CARCINOMA: malignant.

CARCINOSARCOMA: rare, very malignant.

TUBULAR ADENOCARCINOMA: two types, relatively common, malignant

PAPILLARY ADENOCARCINOMA: several types and variations, malignant.

ANAPLASTIC CARCINOMA: very malignant.

Other rare types are possible; some skin tumors can also occur in mammary area

Tumors of the heart are very quite rare and seen infrequently in practice. Clinical signs of these types of tumors include that of congestive heart failure, cardiac arrhythmia, weight loss, poor appetite, fever, general debilitation, weakness and fainting.

FIBROMA: benign solid mass of connective tissues, may interfere with heart function and often internal. The only treatment may be for arrhythmia or congestive heart failure. Otherwise open-heart surgery would be required.

MYOMA: benign tumor originating from muscle tissue, will cause mechanical interference. and possibly conduction disturbances. The only treatment may be for arrhythmia or congestive heart failure. Otherwise open-heart surgery would be required.

RHABDOMYOMA: another benign tumor originating from muscle cells, will also cause mechanical or conduction disturbances and could be trouble to remove. The only treatment may be for arrhythmia or congestive heart failure. Otherwise open-heart surgery would be required.

HEMANGIOSARCOMA: uncommon tumor of heart and blood vessels; much less common than in dogs. Often found on right ventricle of heart and in spleen and liver. Very malignant, this is an ill-defined tumor of vascular (blood vessels) tissue. Will often rupture and cause internal bleeding or sudden death. Cats may often have a history of periodic weakness with spontaneous recovery. Pale gums and loss of weight can also be noted. It will often be too late to help most cats by the time of diagnosis. Surgery to remove large tumors may give cats some quality time.

Masses are often seen on the spleen, liver, intestines and regional tissues accompanied by some degree of intra-abdominal bleeding. Upon exploratory surgery many small tumors (metastasis) are often found. Can also involve the bones and kidneys. Chemotherapy has been tried besides surgery but overall the prognosis is grave for most cats. Cats more commonly have hemangiosarcoma of the skin and surface tissues. ((Hemangiosarcoma)) ((Hemangiosarcoma of the Skin))

HEMANGIOMA: benign cousin of hemangiosarcoma. Most often seen on the skin but these are very rare. May be treated with surgery.

CHEMODECTOMA: very rare tumor of special blood sensor cells in the arteries in or near the neck. Difficult to treat and diagnose.

LYMPHOSARCOMA, CARDIAC: can invade heart and pericardium. see..Lymphosarcoma

MULTIPLE MYELOMA aka PLASMA CELL MYELOMA: a malignant cancer from plasma cells, a cell that produces antibodies. May form solitary tumors but more often spreads and infiltrates in bone, the liver, spleen, nervous system and some other soft tissues. Solitary masses have not been reported in the cat. Can be extremely painful when in the bones. Will causes elevations in one type of blood protein. A rare disease, may be treatable with certain chemotherapy including cortisone.

THYMOMA: tumor of the thymus, a tissue in the chest most active in young cats; part of the immune system. Can be benign or malignant. May compress the heart and lungs and produce pleural effusions leading to cardiac and respiratory dysfunction. May also put pressure on the large blood vessels of the chest. Will also be associated with myasthenia gravis and polymyositis. Quite rare, may be treatable with surgery, chemotherapy and/or radiation therapy. Can be confused with Mediastinal Lymphosarcoma.

THYMIC CYST AND THYMIC ENLARGEMENT: benign and non-neoplastic but may compress heart and lungs causing trouble breathing, fever and swelling of the hindlegs. Treatable with surgery.

Tumors can arise from any of the various liver tissues but more often cancers metastasize to the liver from other sites in the body. Clinical signs of liver tumors are similar to most other liver diseases and include poor appetite, weakness, weight loss, vomiting, diarrhea, increased thirst, fluid collecting in the abdomen, and jaundice. Diagnosis is made in a manner similar to other diseases of the liver.

HEPATOCELLULAR CARCINOMA: a malignant tumor, can be large, small, widespread or nodular. Will often quickly spread to lymph nodes near the liver then to organs nearby. Large solitary tumors or tumors in only one lobe (section) of the liver can be cured with early surgery. Chemotherapy may be helpful in more diffuse cases, however most cats have short survival times after diagnosis.

HEPATOCELLULAR ADENOCARCINOMA: see hepatocellular carcinoma.

HEPATOCELLULAR ADENOMA (HEPATOMA): benign tumor, tends to grow as a large single or multiple masses. Liver will function normally otherwise. Can often be removed with surgery. ((Hepatoma))

BILE DUCT ADENOCARCINOMA: may occur inside or outside the liver or in the gall bladder. (GALLBLADDER ADENOCARCINOMA) Forms from bile duct tissues. May occur as a large mass and be removable, but usually too diffuse for surgery or chemotherapy. More malignant than hepatocellular carcinoma.

LYMPHOSARCOMA, HEPATIC: a nodular or diffuse tumor considered malignant but might respond well to certain types of chemotherapy. see..lymphosarcoma

SECONDARY TUMORS, which metastasize to the liver commonly, include hemangiosacrcoma, mammary gland adenocarcinoma, mast cell tumors and pancreatic carcinoma. ((Metastatic Liver Cancer))

LYMPHOSARCOMA aka LYMPHOMA: a very common and very significant malignant tumor of lymphocytes, a type of white blood cell and an important part of the immune system. Almost all are caused by FeLV. Could be considered a type of leukemia, but considered here because of the distinct clinical syndromes it produces. Spontaneously forms not caused by FeLV do also occur. Could be considered a preventable cancer as there is a vaccine available for FeLV.

This form of cancer has been studied greatly. Four distinct variations are observed:

MULTICENTRIC LYMPHSARCOMA: causes enlargement of all lymph nodes, liver and spleen as these organs fill with abnormal cells. Bone marrow also often affected. Very common form of the disease. May be confused with true lymphoid leukemia.

ABDOMINAL LYMPHOSARCOMA: somewhat common form seen. Will cause single or multiple intestinal masses or a generalized thickening of the bowel and resulting in a malabsorption syndrome. Also will involve abdominal lymph nodes, spleen, liver and kidneys. Most cats are 6-8 years of age. Many not associated with FeLV. It may be possible to remove singular or a few multiple tumors and cure the cat.

MEDIASTINAL LYMPHOSARCOMA: relatively common form which causes enlargement of the area in the chest between the heart and lungs. (mediastinum) Will cause compression of heart and lungs and enlargement of thoracic lymph nodes. Often seen in cats 2-4 years old. Chemotherapy has been quite useful for some cats. ((Lymphosarcoma))

MISCELLANEOUS FORMS: several uncommon presentations of this disease do occur.

Ocular Lymphoma which involves the eye. May be cured by enucleation.

Neural Lymphoma attacking the nervous system and causing varied neurologic deficits.

Renal Lymphoma which caused kidney disease. May be secondary to other lymphomas.

Cutaneous Lymphoma of the skin. Rare in the cat. Treatable.

Nasal Lymphoma attacking the nasal passages. May be treatable.

The clinical signs of lymphoma (LSA) will vary with the type and areas involved. Most cats will have notable enlargement of the lymph nodes which is not painful. Clinical signs in general will otherwise include weakness and decreased activity, poor appetite and weight loss, difficulty swallowing, difficulty breathing, coughing, vomiting, diarrhea, abdominal enlargement and signs otherwise specific to areas involved.

A proper diagnosis is made with blood counts, serum chemical analysis, urinalysis, X-rays, FeLV and FIV testing, lymph node aspirates and biopsy, and a bone marrow biopsy. Surgery is rarely useful as a treatment. For this condition, there are well-established chemotherapy protocols that have a moderate degree of effectiveness. These usually employ multiple drugs given on a specific schedule. A specialist is often needed to perform such therapy. Radiation, has also been employed in some cases. High quality nutritional support is highly recommended. Cats not in remission in several weeks should try some other protocol. Maximum survival with therapy is about 1 year.

METASTATIC NEOPLASIA OF THE LYMPH NODES: because the lymph nodes reflect most any process within the body, inflammatory or neoplastic, their enlargement is often significant. While metastasis to other organs is generally briefly mentioned in this program, it is covered here because of the role of this organ system. Local carcinomas, mast cell tumors, melanoma and other cancers all may cause enlargement of and spread to the lymph nodes. Infections too can lead to enlargement so careful diagnosis is essential.

SERTOLI CELL TUMOR: usually small and benign but can grow very large as part of a retained testicle. Can produce estrogen, which is the most severe effect of the tumor, causing liver and bone marrow damage. Often curable if caught early or chemotherapy may be needed. Surgery on cats with high estrogen levels can be risky. Neutering is preventative.

PROSTATIC ADENOCARCINOMA: malignant tumor, could be seen in cats that have not been neutered. Will cause enlargement of the prostate gland; enlargement will often be quite irregular. Can cause urinary tract blockage, weakness, pain, bleeding from the penis, and weight loss. Spreads to areas inside the pelvis and sometimes other organs. No treatment effective towards a cure but neutering may slow growth of the mass for temporary relief. Almost never seen in castrated males, neutering considered preventative.

Cancers of the muscles are quite rare, but do occur. Cancers occurring in other locations can also spread to muscle tissue but these too are uncommon. Primary muscle tumors include:

RHABDOMYOMA: benign tumor, often localized, can be cured with aggressive surgery if tumor borders can be cleanly identified. Radiation or chemotherapy possible.

RHABDOMYOSARCOMA: very malignant tumor of muscle, can spread wildly through the affected muscle(s). If caught early and removed with very aggressive surgery a cure is possible although not likely. Once tumor spreads the prognosis is quite grave.

While cancers and tumors of the nervous system are uncommon, their composition is often complex and as with any neurologic disease, the location of the mass and nerves or brain tissue affected will determine what symptoms are outwardly seen. Diagnosis of neurologic neoplasms is also difficult and may require a specialist in many cases.

INTRACRAINIAL TUMORS: or tumors of the brain. Pressure on brain tissue and other alterations caused by tumors can lead to seizures, altered levels of consciousness and responsiveness, and deficits of the nerves of the head and face. See..Brain Tumors

SPINAL CORD TUMORS: tumors in this area may occur inside the cord, on surrounding membranes, or put pressure on the spinal cord from surrounding tissues. Damage to this area will obstruct nerve conduction to areas between the tumor and the tail. (literally) Symptoms can include paralysis, weakness and staggering. See..Spinal Cord Tumors

TUMORS OF PERIPHERAL NERVES: neoplasia of the peripheral nerves is quite rare, and otherwise would most commonly occur near the spinal cord where the nerves emerge. Clinical signs include lameness, pain, loss of muscle mass (atrophy), paralysis and licking or chewing at the limb or area affected. See..Peripheral Nerve Tumors

TUMORS OF THE VERTEBRAE AND METASTATIC DISEASE: cancers which spread from the bones, such as osteosarcoma or fibrosarcoma, or cancers which spread to the nervous system from other areas, such as breast, prostate and bladder cancers, can damage the nervous system. Most will produce incurable disease.

Meningioma, Reticulosis, Oligodendroglioma, Astrocytoma and Ependymoma

Meningioma, Astrocytoma, Oligodendroglioma, Neuroepithelioma and Ependymoma

Schwannoma, Neurofibroma, Neurofibrosarcoma and Nerve Sheath Tumors

Tumors of the pancreas may cause symptoms similar to those of pancreatitis, but may include jaundice if the liver or bile ducts become involved. Sometimes a mass may be palpable in the abdomen or abdominal swelling may be noted. Diagnosis is made in a manner similar to other pancreatic conditions.

NODULAR HYPERPLASIA: benign and insignificant. Not neoplastic.

PANCREATIC ADENOMA: benign and usually singular isolated tumor and will rarely cause symptoms. Can be surgically removed but usually not needed.

DUCT CELL CARCINOMA: very malignant and usually will have spread to liver, lymph nodes and lungs before diagnosis is obtained. Can also spread into stomach and intestines. Poor prognosis although some chemotherapy may provide temporary relief.

ACINAR CELL ADENOCARCINOMA: most common tumor of the pancreas; very malignant and usually will have spread to liver, lymph nodes and lungs before diagnosis is obtained. Can also spread into stomach and intestines. Poor prognosis although surgery and chemotherapy may provide temporary relief.

Neoplasia of the respiratory system is uncommon if not frankly rare. Metastatic disease, cancer that spreads to the lungs, is more common. This is why the chest is often X-rayed in cases of breast cancer, lymphosarcoma, mast cell tumors, osteosarcoma, and most any other type of carcinoma found in the body as all can and do find their way into the lungs. Otherwise tumors of respiratory origin are very rare indeed. 

PULMONARY ADENOCARCINOMA: malignant, solid and growing type mass. May be confined to one lobe of the lungs for some time. May cause coughing with blood or difficulty breathing. Surgical removal the best hope.

PULMONARY SQUAMOUS CELL CARCINOMA: cancer of lining tissues, very malignant spreading quickly to lymph nodes and other intrathoracic structures. May cause coughing with blood or difficulty breathing. Possible to remove all or part of a lung if caught early enough.

BRONCHOALVEOLAR CARCINOMA: variation of adenocarcinoma also malignant. Often found as solid mass but can be wide spread through lungs. May cause coughing with blood or difficulty breathing. Surgical removal possible if detected early.

NASAL SQUAMOUS CELL CARCINOMA: malignant cancer of nasal surface tissues, can also invade sinus cavities Can attack or be associated with oral lesions as well. Quick to spread deeply in tissues and then to lymph nodes. Surgery and radiation can be effective but few cats live longer than 6-9 months after diagnosis. To perform surgery one would need to open nasal cavity through bone.

FIBROSARCOMA: malignant tumor of nasal connective tissues. Most common having extended from roof or the mouth, invades deeply but slow to spread to distant sites. Can be partly removed with surgery but most always will regrow. Radiation also effective, and another therapy, injections of Acemannen, has been used with some success. Freezing of the tumor has also been used with some success but access to the cancer may cause difficulty.

A great variety and number of neoplasms occur on the skin. Fortunately, as the skin is exposed to view, the chances for early diagnosis and treatment are equally as opportune. All lumps, bumps, changes in texture or pigmentation of the skin should be investigated, biopsied and removed. Most cases of skin cancer in cats are curable, but the rate of malignancy is higher in cats than in dogs. Two major sub-classes of skin tumors exist; epithelial and adnexal tumors, and mesenchymal tumors.

Epithelial and adnexal tumors arise from the surface layers of skin and their associated structures such as sweat glands, oil glands and so forth. Mesenchymal tumors arise from connective tissues and fat in the deeper layers of the skin.

PAPILLOMA: small benign wart-like tumors, quite rare in the cat. Very benign, may regress spontaneously or can be removed with surgery or freezing.

SQUAMOUS CELL CARCINOMA: very common malignant tumor, also seen in other areas besides the skin. Most common on lighter areas of the skin, especially the earflap, lips, eyelids, nose, face and in the oral cavity. Usually singular but many proliferative and ulcerated. Very invasive and destructive, but slow to metastasize to local lymph nodes. Aggressive surgery, radiation and hyperthermia all useful. Cure depends on extent of tumor and location.

BASAL CELL TUMOR: most common feline skin tumor, usually benign singular masses of middle-age cats. Often well defined, hairless and smooth with some dark in color. May feel solid or soft like a cyst. Surgical removal most always curative. Radiation, chemotherapy and freezing have also been used with success. ((Basal Cell Tumor))

SEBACEOUS GLAND TUMORS: rare tumor of the sebaceous glands. Three types commonly found: Hyperplasia, which is simply over-growth of these tissues. Benign, often found on eyelids, easy to remove. SEBACEOUS GLAND ADENOMA: usually small, darker, multilobulated and singular masses. Benign, slow growing and harmless, some cats will grow large numbers of these tumors. Tends to become a nuisance in some cases if they break or become irritated. Surgical removal curative although many new ones can grow. SEBACEOUS GLAND CARCINOMA: rare malignant tumor, often will grow quickly then ulcerate. Locally very invasive and spreading, variable opinions about chances for metastasis. Very aggressive surgery and/or freezing important for a cure. Radiation also quite useful.

SWEAT GLAND TUMORS: quite rare, rarest of all skin tumors. Most involve what are called the apocrine sweat glands and occur in older cats. Some benign, some malignant, most singular in nature, well circumscribed and firm. Aggressive surgery is curative in most cases although a few will spread to local lymph nodes.

TRICHOEPITHELIOMA: from hair follicle tissues. Most common on the head of older cats, benign, slow growing and well defined. Excellent cure rate with surgery. A rare tumor.

PERIANAL ADENOMA: very rare feline tumor. Tumor forms from glandular tissue in the anus and will grow slowly and progressively, can ulcerate and bleed. Many can be cured with neutering and tumor removal. Freezing, radiation and female hormones have also been used but neutering is most always effective.

APOCRINE GLAND CARCINOMA: extremely rare tumor of glandular tissue of anal sacs, uncommon and moderately malignant. May mimic anal sac abscess in appearance. Surgical removal or freezing the best hope of cure. Will spread to lymph nodes and other parts of the digestive system if not treated early.

FIBROMA: common benign tumor of connective tissue, well-defined, solid, solitary and firm. May be attached to epidermis. Most common in older cats. Easy to cure with surgery.

FIBROSARCOMA: single-site malignant tumor of fibrous tissues in older cats. An unusual multi-focal form can also occur in cats under 5 years of age. All are highly variable in appearance which makes the old adage that "it doesn't look like anything to worry about" quite dangerous. Very locally invasive, many regrow after surgery. Only about 10%, however, will metastasize, usually to the lungs. Some fibosarcomas are poorly differentiated (immature) and known as Spindle Cell Tumors.

It has been noted that there is a statistical incidence of fibrosarcoma associated with areas where a vaccine has been given. Commonly called Vaccine Induced Sarcomas, it is thought that inflammation secondary to the vaccine, ingredients in the vaccine, giving certain vaccines in combination or giving vaccines at the same location repeatedly may have some relationship to the cause of these tumors. It should be clearly noted that the rate of such tumor formation is very low with this author seeing only one such case in over 10,000 cats vaccinated. Further study is ongoing, and because vaccines do so much to improve the quality of cat's lives, pet owners should have little worry about vaccinating their cats.

Very aggressive surgery is important if any hope of cure is desired. Radiation, chemotherapy and acemannen have all also been used with moderate success. Amputation of affected limbs should be performed if deep involvement is present as most cats can be completely cured and will get along quite well. Young cats with the multicentric form of the disease often are infected with the Feline Sarcoma Virus, a rare relative of FeLV; these cats usually cannot be well treated.

LIPOMA: rare, fatty tumor. Benign, well defined and solitary although some cats seem to get multiple tumors. Can grow very large if not removed and will interfere with leg movement. Most grow slowly but progressively. Should be surgically removed as cannot differentiate these form their malignant cousins. Surgery is curative and the only realistic treatment. ((Lipoma))

LIPOSARCOMA: very rare malignant fatty tumor that tends to heavily invade local tissues. Does not arise from a simple lipoma but difficult to differentiate from a lipoma with surgery alone. Should be removed and many can be cured if removed before they invade too much tissue.

MELANOMA: tumor of pigment-producing cells can be benign or malignant although one could not tell by looking at the actual tumor. Occurs very rarely and primarily on the skin. Appears as small, dark, hairless, raised masses with malignant versions larger (not much basis for comparison) than benign tumors. Some may be without pigment so further deception is possible. Very aggressive surgery is important and in some cases, amputation of the area affected should be considered. High cure rate for benign tumors, poor prognosis for malignancy. ((Melanoma))

MYXOMA: very rare benign tumor of embryonic connective tissues. Usually removable with surgery.

MYXOSARCOMA: very rare malignant tumor of embryonic connective tissues. Can invade and infiltrate locally but still may be removable surgically as they are slow to metastasize.

MAST CELL TUMOR: a rare malignant tumor formed from mast cells, which reside along vascular tissues. The skin form of this tumor usually appears as multiple growths on the head and neck; some can grow very large, and all are highly variable as to their outward appearance as to fool anyone who lightly approaches a diagnosis. The mast cells are (most always) very distinct so simple aspiration and cytology can warn the veterinarian of their presence and direct treatment.

Mast cell tumors more often involve the bone marrow, spleen, liver and blood system. Skin tumors often spread to lymph nodes and these other organs. It is sometimes not certain which form came first and both forms are most often present simultaneously. As the cells produce and can release vasoactive substances such as histamines, severe sudden reactions and death can occur. Many turn outwardly red, raw and ulcerated. Cytology is critical before removal of skin tumors so that wide margins are taken around the mass to prevent recurrence.

Adjunctive therapy includes intra-lesion and oral steroids, injection of the area of removal with pure water, other chemotherapeutic drugs and radiation. Internal tumors may respond to cortisone therapy and splenectomy but survival times are often less than a year after such treatment. Aggressive therapy will allow many cats to have some good post-diagnosis time, nevertheless, this is a serious neoplasm and should be dealt with accordingly.

ADENOMA: benign local tumor, can be treated by removing all or part of the affected kidney.

FIBROMA: connective tissue tumor, can spread through the kidneys but will usually not through the body. Can be treated by removing the kidney.

TRANSITIONAL CELL CARCINOMA: tumor of the tubular lining cells of the bladder and related structures, can be rapidly growing but will be slow to spread inside the body. Can produce urinary bleeding, straining and ultimately, restriction of urine outflow. May be treatable by surgical removal of all or part of the bladder and urethra and some type of internal reconstruction. A specialist will usually be required and chemotherapy may also be useful.

SQUAMOUS CELL CARCINOMA: malignant tumor of lining tissues, may act and be treated similar to transitional cell tumors.

ADENOCARCINOMA: malignant tumor of lining tissues, may act and be treated similar to transitional cell tumors.

RENAL CELL CARCINOMA: very malignant and most common tumor of the kidney. Often spreads through all organs of the body, and will generally be untreatable. Chemotherapy may help if caught early. If diagnosed very early removal of the kidney may be possible for a cure. May be caused by poisons and toxins.

EMBRYONAL NEPHROBLASTOMA: often occurs in young cats, very malignant tumor composed of fetal-like tissue, and will quickly spread to lungs, liver, lymph nodes, muscles, bones and joints. In some studies a high survival rate has been achieved with removal of the kidney and ureter followed by chemotherapy.

SECONDARY TUMORS that commonly metastasize to the kidney include hemangiosarcoma, osteosarcoma, malignant melanoma, lymphosarcoma and mast cell tumors.

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