A Nonpediatric Extraosseous Ewing Sarcoma of the Pancreas:Differential Diagnosis and Therapeutic Strategies

Extraosseous Ewing’s sarcoma is a rare and aggressive malignant tumor with a poor prognosis. The pancreas is an extremelyuncommon primary site, with only 27 cases that have been published worldwide. We report a 26-year-old female who presentedwith 5 days of left upper quadrant pain, nausea, and vomiting. On examination, she was anicteric and had epigastric and leftupper quadrant tenderness without guarding, rebound tenderness, or a palpable mass. She had slightly elevated serumaminotransferase and lipase levels. Abdominal computerized tomography revealed a multilobulated tumor arising from thebody and tail of the pancreas. A biopsy confirmed a small round cell tumor, and immunohistochemistry was positive for CD99in approximately 70% of the tumor cells. Afluorescence in situ hybridization (FISH) assay showed a 22q12 rearrangement. Shewas diagnosed with extraosseous Ewing sarcoma of the pancreas and underwent multiagent neoadjuvant chemotherapyfollowed by surgical resection, but subsequent imaging revealed evidence of systemic disease progression. She chose to go onhospice care and died a few weeks later