Primary cutaneous primitive neuroectodermal tumor/Ewing sarcoma: A rare case with an unusual presentation

Abstract

Primitive neuroectodermal tumors (PNET)/Ewing sarcomas (ES) are a group of malignant tumors composed of small round cells of neuroectodermal origin, that affect soft tissue and bone, primarily in children and young adults. About 10%–20% of all cases are extraskeletal, out of which primary cutaneous and superficial cases are rare. We report a case of primary cutaneous PNET/ES in a 57-year-old diabetic man without osseous or other extraskeletal involvement. Differential diagnosis of this rare entity includes other cutaneous malignant round cell tumors such as lymphoma, melanoma, malignant glomus tumor, Merkel cell carcinoma, and malignant cutaneous adnexal neoplasms. The correct diagnosis is important for managing these chemosensitive tumors, which can be achieved with the help of special stains and immunohistochemistry. This case report aims to increase the awareness about rarer clinical presentation of this rare entity with emphasis on histomorphological differential diagnosis.