A perianal gland tumor is a type of

tumor A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

found near the anus in

dog The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the wolf. Also called the domestic dog, it is derived from the extinct Pleistocene wolf, and the modern wolf is the dog's nearest living relative. Do ...

s that arises from specialized glandular tissue found in the

perineum The perineum in humans is the space between the anus and scrotum in the male, or between the anus and the vulva in the female. The perineum is the region of the body between the pubic symphysis (pubic arch) and the coccyx (tail bone), includi ...

. It is also known as a hepatoid tumor because of the similarity in

cell Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery ...

shape to

hepatocyte A hepatocyte is a cell of the main parenchymal tissue of the liver. Hepatocytes make up 80% of the liver's mass. These cells are involved in: * Protein synthesis * Protein storage * Transformation of carbohydrates * Synthesis of cholesterol, ...

s (

liver The liver is a major organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the synthesis of proteins and biochemicals necessary for digestion and growth. In humans, it ...

cells). It is most commonly seen in intact (not

neutered Neutering, from the Latin ''neuter'' ('of neither sex'), is the removal of an animal's reproductive organ, either all of it or a considerably large part. The male-specific term is castration, while spaying is usually reserved for female animals. C ...

) dogs and is the third most common tumor type in intact male dogs. There are two types of perianal gland tumors, perianal gland adenomas, which are

benign Malignancy () is the tendency of a medical condition to become progressively worse. Malignancy is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous ''benign'' tumor in that a malignancy is not s ...

, and perianal gland adenocarcinomas, which are

malignant Malignancy () is the tendency of a medical condition to become progressively worse. Malignancy is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous ''benign'' tumor in that a malignancy is not s ...

. Both have

receptor Receptor may refer to: * Sensory receptor, in physiology, any structure which, on receiving environmental stimuli, produces an informative nerve impulse *Receptor (biochemistry), in biochemistry, a protein molecule that receives and responds to a ...

s for

testosterone Testosterone is the primary sex hormone and anabolic steroid in males. In humans, testosterone plays a key role in the development of male reproductive tissues such as testes and prostate, as well as promoting secondary sexual characteristi ...

. Perianal gland adenomas are three times more likely to be found in intact male dogs than females, and perianal gland adenocarcinomas are ten times more common in male dogs than females. The most commonly affected breeds for adenomas are the Siberian Husky,

Cocker Spaniel Cocker Spaniels are dogs belonging to two breeds of the spaniel dog type: the American Cocker Spaniel and the English Cocker Spaniel of which are commonly called simply Cocker Spaniel in their countries of origin. In the early 20th century, Cock ...

Pekingese The Pekingese (also spelled Pekinese) is a breed of toy dog, originating in China. The breed was favored by royalty of the Chinese Imperial court as a companion dog, and its name refers to the city of Peking (Beijing) where the Forbidden City i ...

, and Samoyed; for adenocarcinomas the most commonly affected breeds are the Siberian Husky,

Bulldog The Bulldog is a British breed of dog of mastiff type. It may also be known as the English Bulldog or British Bulldog. It is of medium size, a muscular, hefty dog with a wrinkled face and a distinctive pushed-in nose.Alaskan Malamute The Alaskan Malamute () is a large breed of dog that was originally bred for its strength and endurance to haul heavy freight as a sled dog and hound. It is similar to other arctic breeds such as the husky, the spitz, the Greenland Dog, Canad ...

. Perianal gland tumors are located most commonly in the skin around the anus, but can also be found on the tail or groin. Adenomas are more common, making up 91 percent of perianal gland tumors in one study. Adenomas and adenocarcinomas look alike, both being round, pink and usually less than three centimeters in width. Adenocarcinomas are more likely to be multiple and invasive into the underlying tissue, and they can

metastasize Metastasis is a pathogenic agent's spread from an initial or primary site to a different or secondary site within the host's body; the term is typically used when referring to metastasis by a cancerous tumor. The newly pathological sites, then, ...

to the lymph nodes,

, and lungs. Both types should be removed and sent to a

pathologist Pathology is the study of the causes and effects of disease or injury. The word ''pathology'' also refers to the study of disease in general, incorporating a wide range of biology research fields and medical practices. However, when used in t ...

for identification. However, 95 percent of perianal gland adenomas will disappear after neutering the dog. Rem emoving the tumor and neutering the dog at the same time will help prevent recurrnce. Dogs with perianal gland adenocarcinomas should be treated with aggressive surgery and the

radiation therapy Radiation therapy or radiotherapy, often abbreviated RT, RTx, or XRT, is a therapy using ionizing radiation, generally provided as part of cancer treatment to control or kill malignant cells and normally delivered by a linear accelerator. Radi ...

and

chemotherapy Chemotherapy (often abbreviated to chemo and sometimes CTX or CTx) is a type of cancer treatment that uses one or more anti-cancer drugs ( chemotherapeutic agents or alkylating agents) as part of a standardized chemotherapy regimen. Chemothe ...

if necessary.

References

{{refend Cancer in dogs