Left Supraclavicular Swelling: Sclerosing Perineurioma.

A sclerosing perineurioma presents as a single asymptomatic papule or nodule located on the hands of adult patients; approximately 60 cases have been reported in medical literature since 1997. Histologically, it originates from the perineural cells of the peripheral nerves and presents epithelial membrane antigen (EMA) positivity and S100 protein negativity. Here, we present the case of a 58-year-old male admitted to our surgery unit complaining of left supraclavicular swelling of 1-cm in size, having no significant past medical history. A lymph node neck tumor was suspected, and the patient underwent surgery under local anesthesia in outpatient care. The intraoperative finding was a whitish mass, wooden-fibrous in consistency, strictly adhering to the skin and apparently fixed to the deep planes. Upon histological examination, a sclerosing perineurioma was diagnosed: neoplastic cells were immunoreactive for CD34, CD99, and EMA, and negative for S100 protein, smooth-muscle actin, pancytokeratin (AE1-AE3), CD31, neurofilaments, and beta-catenin. According to the benign biological tumor behavior, radical resection was considered an adequate treatment. Our case presents as peculiarity the unusual non-acral location (first reported as supraclavicular swelling) and the rare immunopositivity for CD34 and CD99.