osteoid osteoma

n.

A painful benign tumor usually originating in one of the bones of the lower extremities and characterized by a nidus composed of vascularized connective tissue and osteoid material and surrounded by a large zone of thickened bone.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.