A Rare Tumor, a Rare Localization: A Malignant Small Round Cell Tumor in the Thigh

Small round cell malignant tumors are the general term given to tumors that are small, round, and usually develop from undifferentiated cells. Tumors included in this group are: Ewing sarcoma (peripheral neuroectodermal tumor), primitive neuroectodermal tumor, rhabdomyosarcoma, synovial sarcoma, non-Hodgkin lymphoma, cutaneous neuroendocrine carcinoma (Merkel cell carcinoma), retinoblastoma, peripheral neuroblastoma, hepatoblastoma, and nephroblastoma or Wilms’ tumor. In histopathological examinations, positive markers, such as cytokeratin, epithelial membrane antigen, desmin, vimentin, neuron-specific enolase, and CD15, can be found. The patient consulted our clinic with a diagnosis of neuroectodermal small round cell malignant tumor after an excisional biopsy was performed at an external center following a complaint of a mass in the thigh. A 40-year-old female patient with a complaint of a mass in the right femoral posterior region for over 1 year had excisional biopsy performed at an external center with a diagnosis of malignant tumor infiltration. Biopsy material was evaluated by our hospital’s pathology clinic. The result was found to be small round cell malignant tumor. The patient was admitted to our clinic for re-excision. Re-excision was made from the previous incision line on the posterolateral of the right thigh with a 2 mm surgical border. Small round cell tumors are a heterogeneous group of tumors composed of malignant neoplasia. Even though they are often observed in childhood, some primitive neuroectodermal variants may be seen in adults. Owing to their low surveys, early diagnosis and aggressive treatment are significant in these cases.