Juvenile xanthogranuloma. Clinical and pathologic characterization.

The changing name of the juvenile xanthogranuloma bears witness to the evolution of knowledge and experience of its varied clinical and histologic presentations. This study characterizes the clinical, microscopic, and some immunohistochemical features of 34 cases. The salient clinical findings include a bimodal age distribution inclusive of adults, a male:female ratio of 4:1, occasional multiplicity of lesions (20%), and common presentation in the cephalad area. Histologic findings include varied architectural patterns, cellular participation in various proportions by foamy histiocytes, epithelioid monocytes, lymphocytes, plasma cells, eosinophils, Touton giant cells, and spindle cells of two forms (dendritic and fusiform). S100-positive dendritic cells comprised a minor, but important, component at expansion zones. The significance of these findings is described.