Monozygotic twins with congenital self-healing reticulohistiocytosis undergoing BRAFV600E mutation analysis in skin lesion and peripheral blood

Abstract

Congenital self-healing reticulohistiocytosis (CSHR) is a skin-limited form of Langerhans cell histiocytosis (LCH) with neonatal onset and a favorable prognosis; however, some cases progress to a multisystem disease. Here, we report the case of monozygotic twins born at 37 weeks of gestation who exhibited similar eruptions at birth. In twin 1, skin biopsy confirmed LCH, with a BRAFV600E mutation in the skin lesion but not in the peripheral blood. The eruptions in both twins regressed within approximately two months after a course of topical corticosteroids. Both were diagnosed with CSHR. No relapse or new lesions were observed up to four years of age. Therefore, BRAF analysis of lesional skin and peripheral blood may help assess disease status and guide follow-up in patients with CSHR.