Cholecystoduodenal fistula caused by aggressive mucinous gallbladder carcinoma with a porcelain gallbladder.

Cholecystoduodenal fistula secondary to gallbladder carcinoma (GBC) is extremely rare and develops when the tumor penetrates into the adjacent duodenum. A porcelain gallbladder is also a very rare entity that involves the calcification of the gallbladder wall and can be associated with the development of GBC. Herein, we report an unusual case of a patient with cholecystoduodenal fistula, which has been caused by aggressive mucinous gallbladder carcinoma with a porcelain gallbladder. A 68-year-old man was referred to our department due to significant accumulation near the neck of the gallbladder detected by FDG positron emission tomography/computed tomography (PET/CT), which was performed as a check-up of postpneumonectomy for lung cancer. Abdominal contrast CT and magnetic resonance imaging revealed porcelain-like circumferential calcification of the gallbladder wall and a mass in the region detected by FDG PET/CT. Furthermore, upper endoscopy revealed a submucosal tumor with apical ulceration in the posterior wall of the duodenal bulb. Histopathological examination of its biopsy specimen rendered a diagnosis of adenocarcinoma. The patient was preoperatively diagnosed with either gallbladder cancer or duodenal cancer, and subtotal stomach-preserving pancreatoduodenectomy and radical cholecystectomy with gallbladder bed resection were performed. The resected gallbladder revealed a porcelain gallbladder, which formed the cholecystoduodenal fistula. These specimens were histopathologically diagnosed as mucinous adenocarcinoma of the gallbladder with an abundant mucin production.