Aneurysmal bone cyst of the ethmoid.

Although nearly 500 cases of aneurysmal bone cyst have been recorded in the English literature, involvement of the facial bone is uncommon. To our knowledge, this is the first case of extragnathic, facial aneurysmal bone cyst to be reported in the English literature. A left ethmoid aneurysmal bone cyst was found in a 20-year-old pregnant woman who had a 5-month history of progressive left periorbital swelling, left cystic nasal mass, progressive nasal obstruction, blurred vision, and occasional diplopia. The diagnostic evaluation included a sinus series, facial lamiograms, and an EMI scan. Needle aspirates taken frequently from the intranasal cyst consisted of a dark bloody fluid. The surgical procedure, using external rhinotomy approaches, pathologic findings, and a literature review are presented.