Gallbladder Ciliated Foregut Cyst Suspected of Malignancy Preoperatively

Background. Gallbladder ciliated foregut cysts (CFCs) of the lower diaphragm are extremely rare. Furthermore, they are rarely suspected of malignancy preoperatively. Case Presentation. A 50-year-old woman was referred to our hospital for further examination and treatment of a gallbladder tumor that was detected using abdominal ultrasonography (US). After a close inspection, she was diagnosed with a gallbladder tumor that was possibly malignant. Accordingly, open whole layer cholecystectomy was performed because intraoperative US revealed a tumor located on the intraperitoneal side of the gallbladder, and a rapid intraoperative pathological diagnosis identified no malignancy. A postoperative pathological examination revealed a cystic lesion with thin walls covered with ciliated epithelium, which laid on a connective tissue with smooth muscle fibers. Based on the above results, the final pathological diagnosis was CFC of the gallbladder without malignancy. Conclusions. Cases of gallbladder CFC can be considered as cysts requiring treatment owing to CFCs' potential for malignant transformation and high-frequency symptoms.