We report a rare case of Ewing's sarcoma (ES)/primitive neuroectodermal tumor 
(PNET) arising from the adrenal gland. A 17-year-old Japanese woman presented 
with left upper abdominal pain and high fever. Computed tomography and magnetic 
resonance imaging revealed a 15 × 10 cm tumor replacing the adrenal gland. 
Preoperative diagnosis was an adrenocortical carcinoma. Resection of the tumor 
was performed. We obtained the final diagnosis of ES/PNET by immunohistochemical 
molecular study with positive staining for the MIC2 gene product (CD99) and a 
Ewing sarcoma breakpoint region 1 (EWSR1) gene rearrangement. Local recurrence 
was observed one month after the surgery. The patient was then treated with 
systemic chemotherapy and localized radiotherapy.