Haemangiopericytoma of the orbit.

Orbital haemangiopericytomas are ideally managed by complete surgical excision in the first instance. This is frequently not achieved, because difficulty in making the diagnosis preoperatively results in incisional biopsy and the highly vascular nature of the tumour makes complete excision difficult. A series of 12 patients with orbital haemangiopericytoma seen over a 23-year period is presented. The following combination of clinical and radiological features is suggestive of haemangiopericytoma. 1. Painless non-axial proptosis with downward displacement of the globe. 2. Intermittent upper lid swelling. 3. A soft, superiorly located mass with poorly defined borders, especially with a blue hue. 4. A superiorly located, rounded or elongated extraconal mass on CT, isodense with brain, with smooth, well-defined borders and moderate to marked enhancement with the injection of intravenous contrast medium. 5. Significant blush in all three phases of carotid angiography, without prominent arteriovenous shunting. Once haemangiopericytoma is suspected, complete surgical excision is recommended.