Extraosseous Ewing sarcoma and peripheral primitive neuroectodermal tumor of the thyroid gland: Case report and...

The Ewing family of tumors and peripheral primitive neuroectodermal tumor (pPNET) represent different manifestations of the same entity. Immunohistochemical and cytogenetic studies suggest that these tumors have a common origin. Ewing sarcoma is more common in bone, while pPNET is more common in soft tissues. Extraosseous Ewing sarcoma (EoES) is rare. We present the case of a 48-year-old man who presented with acute obstructive respiratory failure secondary to a large thyroid swelling. The patient was initially diagnosed with giant B-cell non-Hodgkin lymphoma and treated with chemotherapy. However, subsequent immunohistochemical staining of biopsy specimens revealed that the patient actually had EoES/pPNET of the thyroid gland. We performed a nearly complete surgical resection of the tumor plus a total laryngectomy and resection of five tracheal rings. However, the patient died of a cerebral metastasis 1 month later after he had completed one cycle of postoperative chemotherapy.