Abstract
A 77-year-old man who was given a diagnosis of gallbladder cancer and preoperative imaging showed an invasive mass lesion in the fundus of the gallbladder. We conducted S4a+5 hepatectomy, cholecystectomy, partial gastrectomy and D2 lymph node dissection. The mucosa of the gallbladder did not have a neoplasm, and the liver and stomach were invaded by a submucosal tumor-like lesion macroscopically. Histopathologically, the tumor consisted mainly of pseudo-sarcomatous proliferative and components which were positive for cytokeratin 7 and vimentin, yielding a diagnosis of sarcomatoid carcinoma of the gallbladder (WHO classification; undifferentiated carcinoma, spindle and giant cell type). Moreover, a fundal type gallbladder adenomyomatosis was observed in the resected specimen, suggesting the possibility that the tumor had arisen from Rokitansky-Achoff sinus (RAS). Adjuvant chemotherapy using gemcitabine was administered, and he is alive without recurrence for 20 months after surgical treatment. To the best of our knowledge, this case is the first reported case of sarcomatoid carcinoma of the gallbladder arising from a fundal type of adenomyomatosis.
