BACKGROUND:Intrahepatic biliary cystadenocarcinoma (IBC)is a low-incidence disease which is often mis- diagnosed because of insufficient recognition.This study aimed to investigate the clinical features,diagnosis and treatment of the disease. METHOD:The clinical data of 4 IBC patients treated in the Second Affiliated Hospital of Sun Yat-Sen University were retrospectively analyzed. RESULTS:The 4 patients complained of right upper abdominal pain and mass or masses.One patient presented with moderate fever and chills,and two had moderately impaired liver function.The levels of carbohydrate antigens(CA125 and CA19-9)were significantly elevated and the level of carcinoembryonic antigen was slightly elevated in 3 patients.The level of serum transaminase was elevated in 2 patients,and the level of serum total bilirubin elevated in 2.Intrahepatic cystic masses ranging from 5.0 to 20.5 cm in diameter were found in all patients by ultrasound and CT/MR scan.Three of the 4 patients were misdiagnosed on admission as having hepatic cyst and one as having hepatic abscess.Radical removal of masses was performed in three patients after pathological diagnosis.One patient died from tumor recurrence 7 years after operation,2 were followed up for 12 and 17 months without evidence of recurrence.The high risk patients who received palliative therapy were closely followed up. CONCLUSIONS:The diagnosis of IBC without specific clinical features mainly depends on imaging and pathological examination.Increased levels of serum CA125 and CA19-9 might contribute to the diagnosis and prognosis of some IBC patients.Radical excision is the only effective treatment. BACKGROUND: Intrahepatic biliary cystadenocarcinoma (IBC) is a low-incidence disease which is often mis-diagnosed because of insufficient recognition. This study aims to investigate the clinical features, diagnosis and treatment of the disease. METHODS: The clinical data of 4 IBC patients treated in the Second Affiliated Hospital of Sun Yat-Sen University were retrospectively analyzed. RESULTS: The 4 patients complained of right upper abdominal pain and mass or masses. One patient presented with moderate fever and chills, and two had moderately impaired liver function. levels of carbohydrate antigens (CA125 and CA19-9) were significantly elevated and the level of carcinoembryonic antigen was slightly elevated in 3 patients. The level of serum transaminase was elevated in 2 patients, and the level of serum total bilirubin elevated in 2. Intrahepatic cystic masses ranging from 5.0 to 20.5 cm in diameter were found in all patients by ultrasound and CT / MR scan.Three of the 4 patients were misdiagno sed on admission as having hepatic cyst and one as having hepatic abscess. Radical removal of masses was performed in three patients after pathological diagnosis. One patient died from tumor recurrence 7 years after operation, 2 were followed up for 12 and 17 months without evidence of recurrence.The high risk patients who received palliative therapy were closely followed up. CONCLUSIONS: The diagnosis of IBC without specific clinical features mainly depends on imaging and pathological examination. Increased levels of serum CA125 and CA19-9 might contribute to the diagnosis and prognosis of some IBC patients. Radical excision is the only effective treatment.