Congenital self-healing reticulohistiocytosis mimicking diffuse neonatal hemangiomatosis.

Congenital self-healing reticulohistiocytosis (CSRH), a rare benign variant of Langerhans cell histiocytosis (LCH), is characterized by (a). congenital skin lesions, (b). a healthy infant with no systemic involvement, (c). the histopathologic finding of a Langerhans cell infiltrate and (d). spontaneous involution within the first year of life without sequelae. We report a Taiwanese girl born with widespread hemangioma-like lesions. The diagnosis of LCH was confirmed by finding a diffuse dermal infiltrate of S-100-protein- and OKT6 (CD1a)-positive mononuclear cells and the presence of Birbeck granules in 10% of the mononuclear cells ultrastructurally. The diagnosis of CSRH was further established by rapid and complete involution of the lesions in 3 months. No recurrence was noted for 7 years. Our case illustrates that CSRH can mimic diffuse neonatal hemangiomatosis clinically; thus, it is important to include CSRH in the differential diagnosis of congenital or neonatal hemangiomatosis.