A case of accessory hepatic duct entering cystic duct successfully treated by laparoscopic cholecystectomy for cholecystolithiasis.

Although laparoscopic cholecystectomy is a well-established surgical procedure, an accessory hepatic duct (AcHD) entering the cystic duct is poorly understood. A 77-year-old woman with symptomatic cholecystlithiasis was referred to our hospital. Abdominal ultrasonography indicated several small stones in the gall bladder. Magnetic resonance cholangiopancreatography (MRCP) did not reveal an anomalous cystic duct. Dissecting the gall bladder bed at operation, AcHD entering the cystic duct was suspected. Intraoperative cholangiography revealed that B5 branch entered the cystic duct. We ligated the AcHD, and divided it. Laparoscopic cholecystectomy was completed, and the patient was discharged without any complication. A week after the operation, MRCP showed that ventral branch of B5 was dilated. The patient showed no symptom for more than a year. The present case exhibited extremely rare AcHD entering the cystic duct, which was hardly recognized before surgery. It is possible to recognize such anomalous variants with standard laparoscopic approach based on 2018 Tokyo Guidelines and with attention to the possibilities of AcHD entering the cystic duct.