Disseminated langerhans cell histiocytosis-related sudden unexpected death in infancy.

Sudden unexpected death in infancy (SUDI) is defined as the sudden and unexpected death of an infant aged less than 1 year and comprises a heterogeneous group of deaths; in around one-third of cases a definite cause of death is identified at autopsy, while almost two-thirds of such deaths will remain unexplained despite a careful review of the circumstances of death and a detailed postmortem examination. We report a case of SUDI due to previously undiagnosed disseminated Langerhans cell histiocytosis (LCH) in a 10-month-old male, a disease characterized by a clonal proliferation of dendritic Langerhans cells. The diagnosis was established on histological examination, which revealed extensive infiltration by LCH of the skin, lymph nodes, thymus, spleen, and lungs.