A Singular Case of Adenomyoma of Ampulla with Parathyroid Adenoma - A Rarest of Rare Association

Adenomyoma is an uncommon benign lesion, rare in the extrahepatic biliary tree and ampulla of Vater, but relatively more common in the gallbladder. Preoperative diagnosis of ampullary adenomyoma is highly challenging, as it often mimics malignancy. We present a case report of a 58-year-old gentleman who presented with abdominal pain and obstructive jaundice to our institution and underwent standard pancreaticoduodenectomy for suspected periampullary malignancy. Surprisingly, the biopsy revealed adenomyoma of the ampulla. Postoperatively, he developed symptoms of hypercalcemia, which, upon further evaluation, was due to a hyperfunctioning left parathyroid adenoma that was subsequently surgically removed. The coexistence of adenomyoma of the ampulla and parathyroid adenoma is exceedingly rare and has not been reported in the literature to the best of our knowledge. We present this unique case report to highlight this singular association, hoping that further research in the future may shed light on this phenomenon. Serum calcium levels should be assessed in all periampullary lesions, as this simple test could have identified the parathyroid adenoma preoperatively.