The biopsy specimen showed cystic spaces lined by amorphous eosinophilic material containing pseudopapillae. Thick fibrous bands of collagen containing fibroblasts were interposed between the cystic spaces. Nodular collections of epithelioid and foamy histiocytes, giant cells, and neutrophils were evident. Polarization did not reveal foreign bodies, and periodic acid–Schiff, gram, and acid-fast bacilli stains did not identify organisms. Because of the asymptomatic nature of the lesions, no further treatment was undertaken.
Upper Extremity Nodules—Diagnosis. Arch Dermatol. 2004;140(2):231-236. doi:10.1001/archderm.140.2.231-h