Verruciform xanthoma: a special epidermal nevus.

Congenital hemidysplasia with ichthyosiform nevus and limb defects (CHILD) syndrome is a rare X-linked hereditary disorder. Presentation varies from ichthyosiform nevus to complete limb amelia. We present a 17-year-old adolescent girl who presented with a 16-cm exophytic mass of the right foot that had been growing for 7 years as well as knee contracture. Deformed nails with onychorrhexis were noted bilaterally. History of multiple nonlinear erythematous skin lesions covered by dry waxy scales involving multiple body folds with sharp midline demarcation was obtained. The patient's family history was negative for consanguinity and similar conditions. Radiography showed right leg hypoplasia and osteopenia. These findings fulfill the diagnosis of CHILD syndrome. Microscopically, psoriasiform epidermal hyperplasia with marked orthohyper-keratosis and neutrophilic exocytosis were noted. The papillary dermis was packed with foamy macrophages consistent with xanthomatous changes, namely verruciform xanthoma. Verruciform xanthoma, although rarely found in other conditions, is a characteristic finding.