Synchronous double primary hepatocellular carcinoma and intrahepatic cholangiocarcinoma in a single patient with chronic hepatitis B: two case reports and literature review.

Simultaneous occurrence of primary hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) is rare. We report two cases of synchronous double primary HCC and ICC (sdpHCC-ICC), both associated with chronic hepatitis B. Case 1 involves a 63-year-old man whose liver lesions were incidentally found during routine screening. Preoperative imaging revealed lesions in the S4 and S5 liver segments, with postoperative confirmation of sdpHCC-ICC. He received hepatic arterial infusion chemotherapy (HAIC) and transcatheter arterial chemoembolization (TACE) combined with gemcitabine and oral S-1 over 26 months, with no recurrence observed. Case 2 describes a 48-year-old woman presenting with right upper abdominal pain. Preoperative imaging identified a lesion at the S6/7 and S8 junction, later confirmed as sdpHCC-ICC. Postoperative TACE was performed at 1.5 and 3 months, and lenvatinib was introduced at 3.5 months. She remained recurrence-free at the 21-month follow-up. While the precise pathogenesis of sdpHCC-ICC remains unclear, chronic HBV infection plays a pivotal role. Surgical resection remains the primary treatment, though prognosis is generally poor due to the ICC component.