Letterer-Siwe Disease [a term no longer in use and now replaced simply by Langerhans cell histiocytosis (LCH)] - is an acute disseminated form of LCH usually seen in newborns and infants. Most cases occur by the age of 2 years. It is characterized by cutaneous, visceral, and bone marrow involvement.
Lesions may be found in skin, bones, liver, spleen, bone marrow, lymph nodes, and lungs. Clinical presentation consists of fever, weight loss, seborrheic skin eruption on front and back of the trunk and over scalp, cytopenias, hepatosplenomegaly, lymphadenopathy, pulmonary infiltrates, and destructive bone lesions.
This skin biopsy from a 7 month old infant with Letterer-Siwe Disease shows a nodular mononuclear infiltrate in the dermis.