Papillary adnexal neoplasm (aggressive digital papillary adenocarcinoma) on the ankle of a 15-year-old girl: case report and review of literature from a pediatric perspective.

Digital papillary adenocarcinoma is a rare malignant tumor of the sweat glands, most commonly encountered in adult males. Only few pediatric cases have been reported, with an apparent predominance of females and none on the ankle. We report a case of a 15-year-old girl with a slowly growing, non-tender mass on the right ankle presenting with difficulty in walking; clinically believed to be a keloid. Excision of the mass revealed a glandular neoplasm with largely eccrine and focally apocrine differentiation. Histologic features do not reliably predict biologic behavior. Because of the existing confusion over the nomenclature, we propose that such tumors be called 'papillary adnexal neoplasms of distal extremities'.