Chondroblastoma of the foot.

A total of 322 cases of chondroblastoma were referred to the Armed Forces Institute of Pathology between 1960 and 1990. Ten additional cases of chondroblastoma were treated at Walter Reed Army Medical Center between 1985 and 1993. Forty-two of these involved the foot, two of which were treated at Walter Reed Army Medical Center. Patients with chondroblastoma of the foot were male in 35 (81%) cases, with a mean age of 25.5 years, which was significantly different from the mean age of 17.3 years in patients with chondroblastoma of the long bones (P < 0.0001). Chondroblastoma of the foot is most commonly found in the posterior subchondral areas of the talus and calcaneus as well as in the calcaneal apophysis. Radiographically, the lesion was associated with an articular surface or apophyseal area in all cases and appeared radiolucent, with little to no matrix production. The margins were generally well defined. Cystic features were noted grossly and histologically in 24 (57%) specimens, a feature seen in only 21% of all chondroblastomas overall. Treatment consists of thorough curetting and bone grafting with good oncologic and functional results.