Primary Pancreas Ewing Sarcoma with Gastric Invasion: A Case Report.

Extraosseous Ewing sarcoma (ES) is a rare malignant tumor with poor prognosis. ES of pancreatic origin is exceedingly rare, with only a few dozen cases documented in the literature. It is a poorly differentiated, aggressive tumor characterized by multiple recurrences and a relatively poor prognosis. Owing to nonspecific imaging findings, it can easily be misdiagnosed as other tumors. Here, we report a case of primary pancreatic ES with direct gastric invasion in a 63-year-old male who presented with melena and summarize previously reported cases of primary pancreatic ES. Radiologists should be aware of the imaging findings of primary pancreatic ES and understand that it may be clinically confused with other tumors because of overlapping imaging features.