A punch biopsy specimen from the central portion of the lesion was broadly ulcerated and contained a diffuse, heavy, inflammatory cell infiltrate. High-power view of the base of the lesion revealed an infiltrate composed of lymphocytes, histiocytes, plasma cells, and numerous eosinophils extending around skeletal muscle bundles. The histiocytic cells did not react to immunoperoxidase staining with antibodies to S100 protein or CD30.
Our patient was treated with 0.05% clobetasol propionate ointment twice daily, which he used on an irregular basis. The lesion cleared completely 1 month after the biopsy was performed, with no recurrence in 8 months of follow-up.