Langerhans cell histiocytosis may be seen with goiter and histiocytic infiltration of the thyroid. We report a 2 ½-year-old boy who had goiter and primary hypothyroidism develop, later had pulmonary disease, and died of neurologic involvement. Autopsy lesions suggested a transitional dendritic cell precursor of the epidermal Langerhans cell. Of the reported cases of Langerhans cell histiocytosis with goiter in children and adolescents, 82% were male when the relative incidence of Langerhans cell histiocytosis is two males to one female. (J Pediatr 1998;132:357-60)