BACKGROUND/AIMS: In order to determine the malignant potential of gallbladder adenoma for progression to carcinoma, we evaluated the histopathologic features of adenoma and adenoma-related lesions on cholecystectomized specimens. METHODS: Among 1,847 cholecystectomized specimens, 63 specimens from 26 benign adenomas, 9 carcinomas in situ (CIS), and 28 invasive carcinomas were selected. A pathologist reviewed all specimens and selected benign adenomas, CIS in the adenoma, and adenoma residue in invasive carcinomas. Adenomas and adenoma-related lesions were classified according to morphology (tubular, tubulopapillary, and papillary) and the consisting epithelium (biliary, pyloric metaplasia, and intestinal metaplasia). The age and the size of the benign adenomas and carcinomas in the adenoma were also compared. RESULTS: Adenoma and adenoma-related lesions were found in 34 out (1.8%) of all resected gallbladder. Among 9 CIS and 28 invasive carcinomas, adenoma-related lesions were detected in 7 and 1 case, respectively. All eight carcinomas arising in the adenoma were well-differentiated solitary tumors. The diameters of the carcinomas in the adenoma were, on average, larger than that of the benign adenomas (1.8 cm vs. 0.9 cm, p=0.01). The patients with carcinomas in the adenoma were, on average, older than those with benign adenomas, although the difference was insignificant (57 years vs. 47 years, p=0.09). The morphology and consisting epithelium did not differ between the benign adenomas and carcinomas in the adenoma. The malignant transformation occurred in 23.5% of adenomas. CONCLUSIONS: Gallbladder adenoma is a rare disease, although malignant transformation occurs frequently. Adenoma is a precancerous lesion and the adenoma-carcinoma sequence is one of the gallbladder cancer carcinogenesis.
Adenoma/epidemiology/*pathology/surgery ; Adult ; Age Factors ; Aged ; Carcinoma/epidemiology/pathology/surgery ; Cell Transformation, Neoplastic ; Cholecystectomy ; Cystadenoma/epidemiology/pathology/surgery ; Female ; Gallbladder Neoplasms/epidemiology/*pathology/surgery ; Gallstones/complications ; Humans ; Male ; Middle Aged ; Neoplasm Invasiveness

At present, surgical treatment is the only curative option for gallbladder (GB) cancer. Many efforts therefore have been made to improve resectability and the survival rate. However, GB cancer has a low incidence, and no randomized, controlled trials have been conducted to establish the optimal treatment modalities. The present guidelines include recent recommendations based on current understanding and highlight controversial issues that require further research. For T1a GB cancer, the optimal treatment modality is simple cholecystectomy, which can be carried out as either a laparotomy or a laparoscopic surgery. For T1b GB cancer, either simple or an extended cholecystectomy is appropriate. An extended cholecystectomy is generally recommended for patients with GB cancer at stage T2 or above. In extended cholecystectomy, a wedge resection of the GB bed or a segmentectomy IVb/V can be performed and the optimal extent of lymph node dissection should include the cystic duct lymph node, the common bile duct lymph node, the lymph nodes around the hepatoduodenal ligament (the hepatic artery and portal vein lymph nodes), and the posterior superior pancreaticoduodenal lymph node. Depending on patient status and disease severity, surgeons may decide to perform palliative surgeries.
Cholecystectomy, Laparoscopic/*methods ; Gallbladder Neoplasms/epidemiology/mortality/*surgery ; Humans ; Incidental Findings ; Laparotomy ; Liver Neoplasms/secondary/*surgery ; Lymph Node Excision/*methods ; Lymph Nodes/pathology/surgery ; Lymphatic Metastasis/*pathology ; Survival Rate