🧬 Vet-Approved Guide to Hemangiopericytoma in Dogs (2025) 🐶

By Dr Duncan Houston BVSc

Hemangiopericytoma is a type of soft tissue sarcoma in dogs that arises from blood vessel support cells called pericytes. These tumors are locally invasive but rarely spread throughout the body. Early recognition and treatment are key to long-term control 🎯. In this 2025 guide, Dr Duncan Houston explains what these tumors are, how they behave, and what your treatment options are 🩺.

🔍 What Is a Hemangiopericytoma?

• 🧪 A tumor from pericytes—cells that support capillaries
• 📍 Appears as a round nodule under the skin, usually on the limbs
• 🩸 May look bald, pigmented, or ulcerated
• ⚠️ Often mistaken for a benign lipoma

It’s considered malignant due to local invasion—but it almost never spreads to distant organs. That said, it tends to regrow if not fully removed 🔄.

🧬 What Are Pericytes?

Pericytes are ancient support cells left over from early embryonic development. They sit along blood vessels and can transform into other cell types as needed. When something goes wrong—like chromosomal damage—they can form tumors instead of repairing tissues 🧠.

🧪 Is Hemangiopericytoma Cancer?

Yes, it’s a malignant soft tissue sarcoma. While it rarely metastasizes (spreads), it is locally aggressive and often comes back if not treated effectively 🧱.

📋 Diagnosis

• 🧫 Fine needle aspirate (FNA) to collect cells
• 🔬 Surgical biopsy or tumor removal for histopathology

A definitive diagnosis often comes after tumor removal and microscopic analysis. These tumors have “tentacles” that invade local tissues, making clean surgical margins essential ✂️.

💉 Treatment Options

1. Surgery

• 🔪 First step in most cases
• 🎯 Goal: remove tumor with wide, clean margins
• ⚠️ Can be tricky due to bleeding and microscopic spread

2. Radiation Therapy

• 💥 Highly effective after surgery
• 📊 80–90% success rate with definitive radiation (15–18 sessions)
• 🩻 Palliative radiation (4–5 treatments) may slow regrowth but doesn’t cure

3. Metronomic Chemotherapy

• 💊 Low-dose, daily oral chemo to slow recurrence
• 🧪 Common drugs: cyclophosphamide + piroxicam
• 🚫 Not for visible tumors—used after surgical removal to delay return

4. Amputation (for limb tumors)

• 🦴 Removes the tumor completely if it’s limb-based
• ✅ Curative if no spread is present
• ⚠️ Considered in younger dogs with difficult-to-remove tumors

5. Watch-and-Wait (select cases only)

• ⏱️ May be appropriate for older dogs or slow-growing tumors
• ⚠️ Risk: tumor regrows more aggressively each time

📉 What If It’s Inoperable?

1. Palliative Radiation

• 📆 Weekly sessions for 3–4 weeks
• 🧘 Reduces pain and slows tumor growth

2. Electrochemotherapy

• ⚡ Delivers chemo more effectively into tumor tissue using electricity
• 💡 Useful when surgery isn’t possible
• 📍 Available only in select specialty hospitals

🧠 Key Takeaways

• 🔬 Hemangiopericytomas are locally invasive but rarely spread
• ✂️ Surgery is the first-line treatment
• 📊 Radiation improves success, especially if margins aren’t clean
• 💊 Metronomic chemo can help delay recurrence
• 🧘 Palliative options exist for tumors that can’t be removed

📲 Final Advice from Dr Duncan Houston

If your dog has a lump—especially on a limb—don’t wait. Hemangiopericytomas look innocent but can become serious if left untreated. The best outcomes come with early, aggressive removal and possible follow-up treatment 🎯.

📱 Need help choosing between surgery, radiation, or palliative care? Download the Ask A Vet App or visit AskAVet.com. We’re here to help your dog get back on their feet—literally 🐾.