Solitary form of congenital self-healing reticulohistiocytosis

Abstract Congenital self-healing reticulohistiocytosis (CSRH) is a rare form of cutaneous Langerhans cell histiocytosis (LCH) that is localized and usually spontaneously resolves without widespread organ involvement. CSRH usually presents cutaneously in many shapes (nodular, vesicular, and bullous) and colors (red, brown, blue, purple), however it rarely occurs as a solitary lesion. The incidence of CSRH is largely unknown due to spontaneous regression and lack of recognition. However, of the 4 LCH cases per million pediatric patients, roughly 20% of all CSRH cases are reported as solitary lesions. We report an unusual solitary cutaneous occurrence of CSRH that was present congenitally.