Juvenile xanthogranuloma in monozygotic twins.

Juvenile xanthogranuloma is usually a benign condition mainly seen in infants and children. It frequently presents as asymptomatic discrete papules on the head, trunk, and limbs. Extracutaneous manifestations, most commonly ocular, are rare but may be associated with significant morbidity. The etiology of juvenile xanthogranuloma is uncertain, although the occurrence in monozygotic twins may suggest genetic predisposition.