Both biopsy specimens demonstrated dense dermal infiltrates of histiocytes with abundant, focally foamy cytoplasm. The cytoplasm of some of the histiocytes contained lymphocytes, plasma cells, and neutrophils (emperipolesis). There was no significant histiocytic atypia. The histiocytes were surrounded by a patchy lymphocytic and plasma cell infiltrate. Immunohistochemical staining revealed that the histiocytes were positive for S100 protein and CD68 and negative for CD1a. Oral prednisone therapy was initiated at a dosage of 60 mg/d for 3 weeks and then tapered over the ensuing 3 weeks. After 6 weeks of treatment, the lesions had nearly resolved.
Multiple Nodules and Plaques on the Face and Trunk—Diagnosis. Arch Dermatol. 2006;142(11):1501–1506. doi:10.1001/archderm.142.11.1501-g