Hemangioma in Dogs and Cats

April 28, 2021 (published)

Hemangiomas are a type of tumor of the blood vessels or the skin. They are benign, but the related hemangiosarcomas are a malignant cancer that also target the blood vessels. They come from the same type of cells and the only difference is that one is malignant.

Hemangiomas arise from a mutation in the cells and the cause is unknown. Research suggests that solar radiation through UV light may play a role when these tumors occur in the skin. Both dogs and cats can get hemangiomas. Depending on where the disease is and its progression, clinical signs can vary. There may be no clinical signs, dark purple blisters on the skin, or internal bleeding causing weakness and anorexia. Treatment and long-term outcome for animals vary depending on the type of tumor.

Who gets hemangiomas?

Both dogs and cats can get hemangioma.

Subcutaneous (under the skin) tumors tend to occur as a single mass. The masses may bleed and bruise easily, contain areas with ulcers and dead tissue, and be painful when touched. Approximately one-third of dogs with subcutaneous form have a history of tumor-associated illness that may include lack of appetite, lethargy, lameness, neurologic abnormalities, cough, voice change, and hemorrhages and/or bruises involving the mass.

Cats and dogs with the skin-related form typically have one or more red to purple skin bumps that are located in areas of sparsely haired, lightly pigmented skin. In dogs, these tumors most commonly occur on the chest and belly, sometimes because they like to sunbathe on their backs. In cats, lesions are most common on lightly colored pinnae (ear flaps) and other areas of the head. Lesions are usually small and nonpainful.

Breeds: American Pitbull Terrier, basset hound, Beagle, Boxer, Dalmatian, English Bulldog, English Pointer, Greyhound, Italian greyhound, Staffordshire terrier, Whippet . These breeds are mostly predisposed to the solar-induced form because they are light-skinned dogs with short hair, especially over the chest and belly – at least in those that like to sunbathe on their backs. However, any breed can get hemangiomas, especially the kind that are not related to the sun.

Sex: Both males and females are equally affected.

Age: Middle aged to older.

Breeds: No breeds are predisposed.

Sex: Both males and female cats are equally affected.

Age: Middle aged to older.


Definitive diagnosis usually requires surgical removal of all or part of a mass and its analysis at a laboratory. Blood tests, clinical signs, and predispositions (age, breed, hair coat color/type, sun exposure history) may suggest that your animal has hemangioma or hemangiosarcoma. Routine blood tests may show anemia. A fluid sample may show cancer cells, although many times these samples only show blood. Your veterinarian may suggest an ultrasound if they suspect hemangioma or hemangiosarcoma before surgery to look for more of an internal mass.

Treatment and Prognosis

The treatment options and long-term prognosis of your pet depends on the type of tumor they have. Once a benign hemangioma is removed surgically, your pet usually requires no additional treatment and is back to normal health. Dogs and cats with solar-induced hemangiomas may develop new hemangiomas (or other solar-induced tumors) at other sites of sun-damaged skin, potentially requiring additional surgeries to remove them.

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