[A case of histiocytosis X of the penis].

A case of localized histiocytosis X of the penis was reported. The patient was a 9-year-old boy who had several tumor lesions on the glans penis and inner layer of prepuce. Biopsy specimens were studied by H-E staining and immunohistochemical staining for S-100 protein (S-100), lysozyme (Lys), leucocyte common antigen (LCA), and Leu-M1. They revealed diffuse infiltration of many atypical histiocytes, which were shown to be S-100+, Lys+, LCA- and Leu-M1-. This indicates that these cells were derived from T-zone histiocyte system. After complete remission of these tumors, the other one arose from anal mucosa. In the literature we could find only one case of a primary penile lesion reported by Myers and others.