Papillomas, Lipomas, Cysts, and Basal Cell Tumors in Dogs
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
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
Treatment: Most histiocytomas disappear spontaneously within one to two
months. Those that persist should be removed for diagnosis.
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
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
Treatment: Basal cell tumors should be removed by wide surgical