Pancreatic Choristoma of the Spleen, a Rare Incidental Finding: A Case Report.

Background: Pancreatic choristoma, alternatively termed ectopic or heterotopic pancreas, denotes pancreatic tissue located outside its standard anatomy and without a direct connection to the main pancreas. The most common sites are the stomach, duodenum, and jejunum, and splenic involvement is very rare. Case Presentation: We report a 37-year-old Afghan male presenting with a progressively enlarging painful mass in the left upper quadrant. Radiological evaluation demonstrated a splenic lesion with suspected extension toward the pancreatic tail; however, imaging findings were non-specific and could not definitively distinguish between a splenic tumor and pancreatic pathology. Because of dense adhesions involving the splenic hilum and concern for malignancy, the patient underwent open splenectomy. Histopathological examination demonstrated pancreatic acini and ductal structures embedded within splenic parenchyma, consistent with pancreatic choristoma. Conclusion: Splenic pancreatic choristoma is very rare and typically found incidentally. Preoperative diagnosis is difficult as imaging findings are non-specific. Histopathology remains the gold standard. Management involves surgical excision, which serves both a diagnostic and curative purpose.