Healthy Dogs

Papillomas, Lipomas, Cysts, and Basal Cell Tumors in Dogs

Lipomas

A lipoma is a benign growth made up of mature fat cells interlaced with fibrous connective tissue. Lipomas are common in overweight dogs, especially females. A lipoma can be recognized by its oblong or round appearance and smooth, soft, fatlike consistency. Lipomas grow slowly and may get to be several inches in diameter. They are not painful. Rarely, what appears to be a lipoma is a malignant variant called a liposarcoma.

Treatment: Surgical removal is necessary if the lipoma is interfering with the dog^’s mobility, is growing rapidly, or is cosmetically bothersome. The tumor should be biopsied if there is any question about the diagnosis.

Histiocytomas

Histiocytomas are rapidly growing tumors found in dogs 1 to 3 years of age. They occur anywhere on the body. These benign tumors are dome-shaped, raised, hairless surface growths that are not painful. Because of their appearance, they are often called button tumors. These benign growths are more common on shorthaired dogs.

Treatment: Most histiocytomas disappear spontaneously within one to two months. Those that persist should be removed for diagnosis.

Sebaceous Adenomas

These are common benign tumors found more often in older dogs, particularly Boston Terriers, Poodles, and Cocker Spaniels. The average age of dogs with sebaceous adenomas is 9 to 10 years.

Sebaceous adenomas arise from the oil-producing sebaceous glands in the skin. They tend to occur on the eyelids and limbs. They may be single or multiple, usually are less than 1 inch (25 cm) across, and appear as smooth, lobulated growths on a narrow base or stem. The surface of the tumor is hairless and may be ulcerated.

Occasionally, a sebaceous adenoma becomes malignant (becoming a sebaceous adenocarcinoma). Suspect malignancy if the tumor is larger than 1 inch, has an ulcerated surface, and is growing rapidly.

Treatment: Small tumors do not need to be removed unless they are causing a problem. Large adenomas should be removed.

Basal Cell Tumors

This is a common tumor usually found on the head and neck in dogs over 7 years of age. It appears as a firm, solitary nodule with distinct borders that sets it apart from the surrounding skin. The tumor may have been present for months or years. Cocker Spaniels appear to be at increased risk.

A small percent of basal cell tumors are malignant, becoming basal cell carcinomas.

Treatment: Basal cell tumors should be removed by wide surgical excision.