UNASSIGNED: Intrahepatic biliary cystadenoma (IBC) is a rare benign cystic tumor of the liver. So far, it has not been comprehensively understood, which causes incorrect diagnosis, treatment confusion, and even inappropriate treatment. Here, we reviewed clinical data of IBC patients in our center, shared our experiences and lessons learned, and improved the level of diagnosis and treatment.
UNASSIGNED: The clinical data of 10 patients with pathologically diagnosed IBC, admitted to the Department of Hepatobiliary Surgery of the Affiliated Hospital of Guangdong Medical University from January, 2007, to January, 2022 were retrospectively analyzed.
UNASSIGNED: 10 patients underwent surgery and were discharged successfully. Cyst morphology: multiple cysts: 6 cases (6/10), monocular cyst: four cases(4/10). Six patients (6/10) were diagnosed as IBC preoperatively and received hepatectomy. Four patients with monocular cyst IBC underwent intraoperative frozen section examination, except one case showed IBC; the rest were misdiagnosed as simple liver cyst. In three misdiagnosed patients, one underwent open left hepatectomy seven days after the initial operation. The other patient refused to undergo reoperation and required follow-up observation. The last patient could not tolerate hepatectomy due to insufficient residual liver volume and chose follow-up observation.
UNASSIGNED: For IBC, especially monocular IBC, it is easy to be misdiagnosed as simple hepatic cyst, which brings great confusion to clinical treatment. We propose strengthening communication with pathologists to deepen understanding of IBC. Attention should be paid to the cyst wall\'s shape and the cyst fluid\'s properties during the operation to avoid the missed diagnosis, misdiagnosis, or even improper operation. For suspicious cases, directly choose hepatectomy to avoid reoperation after thoroughly evaluating the patient\'s condition.

BACKGROUND: Intrahepatic biliary cystadenoma (IBC) is a rare benign hepatic tumor that is often misdiagnosed as other hepatic cystic diseases. Therefore, imaging examinations are required for preoperative diagnosis. Contrast-enhanced ultrasound (CEUS) has gained increasing popularity as an emerging imaging modality and it is considered the primary method for screening IBC because of its specificity of performance. We describe an unusual case of monolocular IBC and emphasize the performance of CEUS.
METHODS: A 45-year-old man complained of epigastric pain lasting 1 wk. He had no medical history of hepatitis, liver cirrhosis or parasitization. Physical examination revealed a mass of approximately 6 cm in size in the upper abdomen below the subxiphoid process. Tumor marker tests found elevated CA19-9 levels (119.3 U/mL), but other laboratory tests were unremarkable. Ultrasound and computerized tomography revealed a round thick-walled mass measuring 83 mm × 68 mm located in the left lateral lobe of the liver that lacked internal septations and manifested as a monolocular cystic structure. CEUS demonstrated that in the arterial phase, the anechoic area manifested as a peripheral ring with homogeneous enhancement. The central part presented with no enhancement. During the portal phase, the enhanced portion began to subside but was still above the surrounding liver tissue. The patient underwent left partial liver lobectomy and recovered well without tumor recurrence or metastasis. Eventually, the results of pathological examination confirmed IBC.
CONCLUSIONS: A few IBC cases present with monolocular characteristics, and the lack of intracystic septa in imaging performance cannot exclude IBC.

Apatinib is a new oral tyrosine kinase inhibitor that targets vascular endothelial growth factor receptor-2. It has been proven effective in treating multiple solid tumors. Herein, we report the case of a 67-year-old Chinese patient who was diagnosed with recurrent and malignant transformation of intrahepatic biliary cystadenoma. After multidisciplinary team discussion, the team considered that the remaining liver volume was insufficient for surgical resection. The patient refused chemotherapy and radiotherapy and was willing to take apatinib. Initially, the patient experienced severe tongue ulcers and difficulty eating. The dose of apatinib was then adjusted to 250 mg/day. To date, he has been taking apatinib for 48 months. Regular re-examination showed that the tumor had significantly decreased in size. On January 16, 2021, a CT scan revealed a tumor diameter of 4.5 cm. In our case, the patient achieved partial response and progression-free survival(PFS) of 48.0 months. During treatment, the patient\'s appetite and mental state were expected. The treatment did not induce hypertension, fatigue, hand-foot syndrome, or liver and kidney damage. Apatinib may be an option for the treatment of advanced intrahepatic biliary cystadenocarcinoma. Its toxicity is controllable and tolerable. The exact curative effect still needs to be evaluated in more cases.

Intrahepatic Biliary Cystadenoma (IBC) is rare but has a high incidence of misdiagnosis, especially for experienceless surgeons.
We report a case of IBC located in the caudate lobe and described a typical procedure of misdiagnosing this disease. Finally, the patient was successfully cured, but the procedure of misdiagnosis should attract attention. IBC and atypical biopsy for histological examination are the most important causes of misdiagnosis. Recurrent cystic lesions of the liver and repeated increases in CA 19-9 may suggest a \"liver cyst\", which is a misdiagnosis.
The experience and lessons of misdiagnosis, in this case, may help other clinicians diagnose the rare disease accurately.

OBJECTIVE: To investigate preoperative differential diagnoses made between intrahepatic biliary cystadenoma and intrahepatic biliary cystadenocarcinoma.
METHODS: A retrospective analysis of patient data was performed, which included 21 cases of intrahepatic biliary cystadenoma and 25 cases of intrahepatic biliary cystadenocarcinoma diagnosed between April 2003 and April 2013 at the General Hospital of PLA. Potential patients were excluded whose diagnoses were not confirmed pathologically. Basic information (including patient age and gender), clinical manifestation, duration of symptoms, serum assay results (including tumor markers and the results of liver function tests), radiological features and pathological results were collected. All patients were followed up.
RESULTS: Preoperative levels of cancer antigen 125 (12.51 ± 9.31 vs 23.20 ± 21.86, P < 0.05) and carbohydrate antigen 19-9 (22.56 ± 26.30 vs 72.55 ± 115.99, P < 0.05) were higher in the cystadenocarcinoma subgroup than in the cystadenoma subgroup. There were no statistically significant differences in age or gender between the two groups, or in pre- or post-operative levels of alanine aminotransferase, aspartate aminotransferase, total bilirubin (TBIL), and direct bilirubin (DBIL) between the two groups. However, eight of the 21 patients with cystadenoma and six of the 25 patients with cystadenocarcinoma had elevated levels of TBIL and DBIL. There were three cases in the cystadenoma subgroup and six cases in the cystadenocarcinoma subgroup with postoperative complications.
CONCLUSIONS: Preoperative differential diagnosis relies on the integration of information, including clinical symptoms, laboratory findings and imaging results.