Letterer-Siwe disease

Letterer-Siwe disease is a condition where histiocytes proliferate in the body. It is sometimes classified as a form of Langerhans cell histiocytosis, or as a disseminated form of histiocytosis X. It is most commonly seen in children less than two years old.

Symptoms include lymphadenopathy, hepatosplenomegaly, and seborrhea-like lesions on the skin. Untreated, the disease is fatal. The five-year survival rate with treatment is fifty percent.