Hemangiopericytoma

Description of Orbital Tumors – Hemangiopericytoma

Hemangiopericytoma is a tumor that develops from the cells surrounding the small blood vessels (pericytes). It is a rare, soft tissue sarcoma and involves the contractile cells wrapping around the endothelial cells. It can involve blood vessels in the conjunctiva, choroid, optic nerve or skin of the medial canthus. Hemangiopericytoma accounts for only 1-3% of all biopsied orbital lesions and 1% of all lacrimal sac tumors. It can be benign or malignant and can spread to other parts of the body. This type of tumor impacts one in a million and is more common in women than in men.

Pathophysiology of Orbital Tumors – Hemangiopericytoma

Hemangiopericytoma of the orbit is caused by an unusual layering of pericytes around malformed blood vessels. The tumor cells are formed from pluripotent mesenchymal cells. The main pathological characteristic is the vascular structure and the positive staining for markers like CD34 and vimentin on the tumor cells. They grow slowly and are usually well-encapsulated. Sometimes they can grow more rapidly which increases the chance of metastasis.

Symptoms and Signs of Orbital Tumors – Hemangiopericytoma

Hemangiopericytoma can exist without symptoms, particularly in early stages. As the tumor grows, patients may develop a painless or tender lump. Swelling can present as proptosis and exophthalmos. There is a potential for raised orbital pressure and/or watering of the eyes. Visual loss and decreased extraocular muscle motility may also be concerns depending on location of the tumor. Neurological issues can occur for those patients with tumors in the brain or spinal cord.

Diagnosis of Orbital Tumors – Hemangiopericytoma

Clinical examination and a review of symptoms can usually determine a diagnosis. CT scans and MRIs may assist in confirming that diagnosis and in planning surgical excision. Note that hemangiopericytomas can be mistaken for other orbital masses like fibrous histiocytoma, hemangioma, glomus tumor, sarcoma, and vascular malformation.

Treatment of Orbital Tumors – Hemangiopericytoma

At Idaho Eyelid and Facial Plastic Surgery, treatment depends on several factors related to size and location of the tumor. The level of aggressive tumor growth is also a factor in determining a treatment option. Surgical removal is the primary treatment for hemangiopericytomas; however, radiation therapy to shrink tumors and chemotherapy may also be used. Smaller tumors that are surgically removed have a better prognosis. Overall, there is almost a 90% five-year-survival rate seen in hemangiopericytoma. Local recurrence is possible, but distant metastasis to the lung, liver, bone and mediastinum is rare.