A perianal gland tumor is a type of tumor

Tumor

A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...

 found near the anus

Anus

The anus is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, unwanted semi-solid matter produced during digestion, which, depending on the type of animal, may be one or more of: matter which the animal cannot digest,...

 in dog

Dog

The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...

s that arises from specialized glandular tissue found in the perineum

Perineum

In human anatomy, the perineum is a region of the body including the perineal body and surrounding structures...

. Perianal glands do not exist in cat

Cat

The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...

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

Cell (biology)

The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

 shape to hepatocyte

Hepatocyte

A hepatocyte is a cell of the main tissue of the liver. Hepatocytes make up 70-80% of the liver's cytoplasmic mass.These cells are involved in:* Protein synthesis* Protein storage* Transformation of carbohydrates...

s (liver

Liver

The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...

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

Neutering

Neutering, from the Latin neuter , is the removal of an animal's reproductive organ, either all of it or a considerably large part. The process is often used in reference to males whereas spaying is often reserved for females. Colloquially, both terms are often referred to as fixing...

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

Adenoma

An adenoma is a benign tumor of glandular origin. Adenomas can grow from many organs including the colon, adrenal glands, pituitary gland, thyroid, prostate, etc. Although these growths are benign, over time they may progress to become malignant, at which point they are called adenocarcinomas...

s, which are benign

Benign

A benign tumor is a tumor that lacks the ability to metastasize. Common examples of benign tumors include moles and uterine fibroids.The term "benign" implies a mild and nonprogressive disease. Indeed, many kinds of benign tumors are harmless to human health...

, and perianal gland adenocarcinoma

Adenocarcinoma

Adenocarcinoma is a cancer of an epithelium that originates in glandular tissue. Epithelial tissue includes, but is not limited to, the surface layer of skin, glands and a variety of other tissue that lines the cavities and organs of the body. Epithelium can be derived embryologically from...

s, which are malignant

Malignant

Malignancy is the tendency of a medical condition, especially tumors, to become progressively worse and to potentially result in death. Malignancy in cancers is characterized by anaplasia, invasiveness, and metastasis...

. Both have receptor

Receptor (biochemistry)

In biochemistry, a receptor is a molecule found on the surface of a cell, which receives specific chemical signals from neighbouring cells or the wider environment within an organism...

s for testosterone

Testosterone

Testosterone is a steroid hormone from the androgen group and is found in mammals, reptiles, birds, and other vertebrates. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands...

. 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

Siberian Husky

The Siberian Husky is a medium-size, dense-coat working dog breed that originated in north-eastern Siberia. The breed belongs to the Spitz genetic family...

, Cocker Spaniel, Pekingese

Pekingese

The Pekingese, or "Peke" is an ancient breed of toy dog, originating in China. The breed was favored by the Chinese Imperial court, and its name refers to the city of Beijing where the Forbidden City resides...

, and Samoyed

Samoyed (dog)

The Samoyed dog takes its name from the Samoyedic peoples of Siberia. An alternate name for the breed, especially in Europe, is Bjelkier...

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

Bulldog

Bulldog is the name for a breed of dog commonly referred to as the English Bulldog. Other Bulldog breeds include the American Bulldog, Olde English Bulldogge and the French Bulldog. The Bulldog is a muscular heavy dog with a wrinkled face and a distinctive pushed-in nose...

, and Alaskan Malamute

Alaskan Malamute

The Alaskan Malamute is a generally large breed of domestic dog originally bred for use as a utilitarian dog and later an Alaskan sled dog. They are sometimes mistaken for a Siberian Husky, but in fact are quite different in many ways...

.

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

Metastasis, or metastatic disease , is the spread of a disease from one organ or part to another non-adjacent organ or part. It was previously thought that only malignant tumor cells and infections have the capacity to metastasize; however, this is being reconsidered due to new research...

 to the lymph node

Lymph node

A lymph node is a small ball or an oval-shaped organ of the immune system, distributed widely throughout the body including the armpit and stomach/gut and linked by lymphatic vessels. Lymph nodes are garrisons of B, T, and other immune cells. Lymph nodes are found all through the body, and act as...

s, liver

Liver

The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...

, and lung

Lung

The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...

s.

Both types should be removed and sent to a pathologist for identification. However, 95 percent of perianal gland adenomas will disappear after neutering the dog. Removing the tumor and neutering the dog at the same time will help prevent recurrence. Dogs with perianal gland adenocarcinomas should be treated with aggressive surgery and the radiation therapy

Radiation therapy

Radiation therapy , radiation oncology, or radiotherapy , sometimes abbreviated to XRT or DXT, is the medical use of ionizing radiation, generally as part of cancer treatment to control malignant cells.Radiation therapy is commonly applied to the cancerous tumor because of its ability to control...

 and chemotherapy

Chemotherapy

Chemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen....

if necessary.