“Wnt/β-catenin-activated Ewing's sarcoma with metastasis to pancreas:” A rare case report

Ewing's sarcoma (ES) family of tumors are aggressive tumors with high metastatic potential. Various unusual sites of metastasis have been reported, with pancreas being one of the exceptional sites. Herein, we report a case of a 21-year-old biopsied for a pancreatic mass and its histopathological evaluation revealed infiltration by a malignant small round cell tumor. Given that the patient was under treatment for ES of the right iliac bone an immunohistochemistry panel applied showed CD99, FLI-1 positivity proving it to be a metastasis. Furthermore, β-catenin put on clinical suspicion of solid pseudopapillary neoplasm was positive. Recent evidence suggest that elevated β-catenin expression is associated with poor outcomes, signifying Wnt/β-catenin signaling pathway contributes to disease progression. We not only report an uncommon metastasis of ES to the pancreas with four other cases reported so far but we also attempt to analyze probable correlation of β-catenin to disease advancement and its prognostic implication.