Steatocystoma multiplex and leuconychia in a child with Alagille syndrome.

Alagille syndrome is a rare autosomal dominant developmental disorder, characterized by congenital paucity of interlobular bile ducts, peculiar facies, posterior embryotoxon, bone abnormalities, and peripheral pulmonary artery stenosis. Cutaneous involvement in this disorder is quite rare and the association of Alagille syndrome with multiple comedones and cysts has been described only once. Here, we report the clinical and histological findings of a 7-year-old patient affected by Alagille syndrome who presented multiple cystic lesions and comedones reminiscent of steatocystoma multiplex and a congenital total true leuconychia. Although unexplained, the association of this syndrome with a developmental disorder of the pilosebaceous unit may not be fortuitous.