Spontaneous necrosis of solid gallbladder adenocarcinoma accompanied with pancreaticobiliary maljunction

A 71-year-old Japanese man with acute cholecystitis and an incarcerated gallbladder （GB） stone was admitted. Plain ultrasonography （US） incidentally detected a mass-like lesion in the fundus. Doppler US revealed that this elevated lesion had no blood flow. Computed tomography showed a relatively low-density mass, measuring 5 cm x 4 cm in diameter, with no positive enhancement. Magnetic resonance imaging showed a mass in the fundus with a slightly low intensity on Tl-weighted images and a slightly high intensity on T2-weighted images. We were agonized in making the qualitative diagnosis of mass-like lesions of the fundus, such as a benign tumor, cancer, or debris. We performed laparoscopic cholecystectomy, because the incarcerated GB stone clearly caused acute cholecystitis. Intra-operative cholangiography clearly revealed pancreaticobiliary maljunction. Amylase levels in the common bile duct and gallbladder were quite high. The elevated lesion in the fundus dearly showed severe necrosis. Although this necrotic nodule included non-viable adenocarcinoma cells, viable cancer cell nests were located in the muscularis propria and subcutaneous layer. Histopathological examination confirmed a solid adenocarcinoma. Thus, we diagnosed it as a gallbladder cancer, based on histopathological analysis of the resected specimen. We therefore undertook radical surgery, including wedge resection of the liver, radical dissection of regional lymph nodes, and resection of the extrahepatic bile duct. Histopathological findings revealed no cancer, hyperplasia or dysplasia in the additionally resected specimens. The patient was finally staged as T2, N0, H0, P0, M（-）, stage Ⅱ. We present the first case of spontaneous necrosis of solid gallbladder adenocarcinoma, with a review of previous studies.