Traumatically induced inclusion cyst secondary to shoe impingement: report of three cases.

Three cases of traumatically induced inclusion cyst affecting the dorsal aspect of the first metatarsophalangeal joint are presented. Though each case was unique, the clinical presentation was similar with patients relating discrete callus formation with a central sinus overlying an enlarging mass. In all cases, the lesion site involved the dorsal first metatarsophalangeal joint and specifically corresponded to the throatline of "pump" shoes that these patients commonly wore. Predisposing factors in these cases appeared to be forefoot equinus deformity with extensus contractor of the extensor hallucis longus tendon and use of pump shoes with a constricting throatline. The authors describe a surgical approach for treatment of this condition, which addresses underlying etiologies of inclusion cyst formation. Pathology was consistent with traumatically induced inclusion cyst. Though inclusion cysts are common in the foot, rarely is the dorsum of the foot involved, and this article, to the authors' knowledge, is the first to be reported in the podiatric literature.