Diagnostic Pathology

Adamantinoma-like ewing sarcoma arising in the pancreatic tail: a case report of a rare entity and review of the literature

The study presents a unique case of Adamantinoma-like Ewing Sarcoma (ALES) in the pancreatic tail, an atypical location for this rare subtype of Ewing sarcoma. A 43-year-old male patient with epigastric pain underwent surgery for a suspected pancreatic tumor, revealing infiltrative growth involving both the pancreatic tail and adrenal gland. Microscopic analysis demonstrated small round blue cell nests with epithelial differentiation, resembling adamantinoma. Immunohistochemistry confirmed positivity for cytokeratins, P40, CK5/6, CD99, and NKX2.2, along with variable FLI1 expression. Fluorescence in situ hybridization confirmed the EWSR1-FLI1 gene fusion. The case highlights the diagnostic complexities when ALES occurs in uncommon sites and contributes to understanding this unique subtype of Ewing sarcoma.