Mitotically active xanthogranuloma: a case report with review of the literature.

Juvenile xanthogranuloma is a benign histiocytic lesion that displays different histologic patterns. The classic form consists of a proliferation of foamy histiocytes admixed with numerous multinucleated Touton-type giant cells, lymphocytes, and eosinophils. Mitotic figures are rare or even absent. Apart from this classic form, a nonlipidized form showing a diffuse infiltrate of nonfoamy histiocytes with or without rare Touton-type giant cells is described. The mitotic activity is somewhat higher than in the classic form. We describe here an unusual case, occurring in a 71-year-old man, characterized by a very high mitotic index (22 mitotic figures per 10 high-power fields).