Adenocarcinoma in Cats
While anal gland/sac cancer (adenocarcinoma) is not common, it is an invasive disease that does not generally have a positive outlook. Usually seen as a rectal growth (mass) on a cat, it is also common to find the disease in the lymph nodes. Due to the type of disease, it is typically cancerous (malignant) and can spread quickly into other areas of the cat's body. There are treatment options available, usually surgical, that can help to improve an animal's chances for survival.
The most common sign of anal gland cancer is a rectal mass or tumor. The tumors are often small in nature. In addition to the visible signs of a tumor, cats that are suffering from the disease may be constipated or have difficulty defecating (obstipation), have a loss of appetite (anorexia), be excessively thirsty (polydipsia), and may seem lethargic.
This disease is fairly rare in cats. There is currently no breed that is a most prone to this type of cancer, but it is often associated with a hormone imbalance (parathyroid), as it is often found in the anal/genital area. It is also linked with high levels of calcium (hypercalcemia) in the body.
A fine needle is inserted into the cancerous anal mass (aspirate) and the cells are examined to rule out any other possible conditions. It can be challenging to determine whether the mass is malignant or not, so the needle biopsy is a useful diagnostic test. In some cases an incision and a full biopsy are needed to properly diagnose the mass. Some veterinarians will also use imaging tools to look at the mass, such as X-rays or ultrasounds.