Orbital myopericytoma: an unusual tumor in an unusual location.

A 71-year-old male with a 4-month history of bulging, tearing, and redness in the right eye presented with vision loss, proptosis, conjunctival hyperemia, and chemosis. Magnetic resonance imaging showed a right intraconal solid mass with extraconal extension, hyper-intense in T2 sequences with heterogeneous contrast enhancement. Complete excision of the mass was performed through a lateral orbitotomy. Histological analysis revealed a neoplasm with high vessel density, solid growth of oval cells, a concentric proliferation of the wall of small vessels, and a weak and patchy positivity for smooth muscle actin. These findings were consistent with the diagnosis of myopericytoma. After surgery, visual acuity improved in the affected eye and after 18 months of follow-up there have been no signs of recurrence.