Cutaneous aneurysmal bone cyst-First report of a case and literature review.

Aneurysmal bone cyst (ABC) is a benign, expansile, multiloculated and blood-filled cystic lesion most commonly involving bones. We report herein the case of a 78-year-old woman with a dermal ABC located in the skin of the right foot. Histologically, the lesion displayed characteristic features of ABC, including blood-filled cystic spaces lined by loose connective tissue, admixed with solid areas composed of spindle cells and osteoclast-like giant cells, associated with foci of woven bone formation and matrix calcification ("blue bone" formation).