Hemangiopericytoma is a soft tissue tumor that arises from pericytes, the cells that surround capillaries and small blood vessels. It is considered a type of peripheral nerve tumor or mesenchymal neoplasm.

• It occurs mainly in middle-aged and older dogs (6-14 years old).
• It is benign locally, but can recur if not completely removed.

Symptoms:

• A slow-growing tumor under the skin, usually on the limbs, trunk or neck,
• does not cause pain, can reach large sizes, often without symptoms.

Diagnosis:

• Fine needle aspiration (usually uninformative),
• biopsy and histology - the main diagnostic method,
• Ultrasound, X-ray or CT scan - to determine the depth of the lesion and plan the operation,
• MRI if indicated (especially if nerve or joint damage is suspected).

Treatment:

• Surgical excision is the mainstay of therapy, with wide excision recommended.
• Radiation therapy is indicated after incomplete removal or if radical resection is not possible, it helps to control growth and reduce the risk of recurrence.
• Chemotherapy is rarely used, but may be considered for invasive or recurrent tumors.