Ectopic orbital meningioma: report of two cases and literature review

Abstract

Ectopic orbital meningioma is a rare tumor usually affecting the medial orbit. We present two cases that occurred in a 56-year-old woman and a 28-year-old man. The tumors in both patients were subtotally excised via orbitotomy surgery and were located in the superior quadrant in one of our patients and in the temporal quadrant in the other. Following histopathologic diagnosis, external beam radiotherapy (EBRT) was administered to one patient and intensity modulated radiotherapy to the other. We identified 12 other well-documented cases of ectopic orbital meningioma previously reported. Ectopic meningioma should be considered in the differential diagnosis of medial as well as lateral and superior orbital tumors. The tumor is usually well circumscribed but can be ill defined in imaging studies. There are intralesional calcifications and sclerosis of adjacent bone in some cases. Ectopic orbital meningioma can recur after incomplete excision. Based on the efficacy of EBRT in optic nerve sheath meningioma, we used this treatment to decrease the risk of recurrence in our two patients and found no tumor recurrence at follow-ups of 24 and 74 months, but one patient had severe vision loss from radiation retinopathy.

Keywords: ectopic meningioma; external radiotherapy; magnetic resonance imaging; orbit; radiation retinopathy.