An expansile myxoid nodule was seen in the dermis. The overlying epidermis was focally eroded, and its rete ridges were effaced. The tumor contained cords of epithelioid cells with eosinophilic cytoplasm in a mucinous stroma. Some cells were large and contained prominent vacuoles that displaced the nucleus to the periphery (physaliferous cells). Immunohistochemical analysis revealed that the tumor cells were positive for S100 protein and cytokeratins and negative for calponin.
Bluish Papule in a Middle-aged Man—Diagnosis. Arch Dermatol. 2005;141(12):1595-1600. doi:10.1001/archderm.141.12.1595-f