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Invasive micropapillary variant of the gallbladder adenocarcinoma and its aggressive potential for lymph node
Seiichi Hara1, Hiroshi Kijima, Ken-ichi Okada
1Division of Gastroenterology and Hepatology, Department of Internal Medicine, Toho University Omori Medical Center, Tokyo, Japan.
Abstract:
An invasive micropapillary variant (IMPV) has recently been described in several organs but has not been reported in the gallbladder. It has been mentioned to have aggressive behavior with a high propensity for lymphovascular invasion, lymph node metastasis and poor clinical outcome. We analyzed the clinicopathologic findings of IMPV and compared them with those of a conventional adenocarcinoma in the gallbladder to clarify the highly aggressive potential of IMPV of gallbladder carcinoma. Ninety consecutive cases of surgically resected gallbladder carcinomas were studied for age, gender, type, depth of invasion and lymph node and distant metastases. Histologically, IMPV of gallbladder carcinoma was characterized by a small cluster of tumor cells lying within clear stromal spaces. This pattern mimicked extensive lymphatic invasion, but the cluster of tumor cells showed a distinctive retraction artifact from the surrounding stroma. In total, 20 (22.2%) cases had foci of IMPV, which ranged from 5% to 10% of the primary tumor tissue. Of those 20 cases, 17 (85.0%) carcinomas with IMPV also included lymph node metastasis, which was more frequent than in conventional carcinoma (32.8%, P < 0.001). Carcinomas with IMPV had a more advanced tumor status and showed severe lymphatic invasion (P = 0.001, P < 0.001, respectively). A multivariate regression analysis demonstrated that the presence of IMPV is an independent predictor of regional nodal metastasis (Odds ratio: 9.995, 95% confidence interval: 1.996-50.052, P = 0.005). IMPV is a useful predictor of regional lymph node metastasis in gallbladder adenocarcinoma.
Insights
The invasive micropapillary variant (IMPV) of gallbladder carcinoma is associated with aggressive behavior and significantly higher lymph node metastasis rates compared to conventional types. Identifying IMPV aids in predicting regional nodal spread in gallbladder adenocarcinoma.
Area of Science:
- Oncology
- Pathology
- Surgical Oncology
Background:
- The invasive micropapillary variant (IMPV) is recognized for its aggressive behavior in various organs.
- IMPV has not been previously reported in gallbladder carcinoma.
- This variant is associated with lymphovascular invasion, lymph node metastasis, and poor outcomes.
Purpose of the Study:
- To analyze clinicopathologic findings of IMPV in gallbladder carcinoma.
- To compare IMPV with conventional gallbladder adenocarcinoma.
- To clarify the aggressive potential of IMPV in gallbladder carcinoma.
Main Methods:
- Retrospective analysis of 90 consecutive surgically resected gallbladder carcinomas.
- Histological examination to identify IMPV characterized by tumor cell clusters in clear spaces with retraction artifact.
- Comparison of clinicopathologic features between IMPV and conventional adenocarcinoma.
Main Results:
- Foci of IMPV were identified in 20 (22.2%) cases.
- Carcinomas with IMPV showed significantly higher lymph node metastasis rates (85.0%) compared to conventional types (32.8%, P < 0.001).
- IMPV was an independent predictor of regional nodal metastasis (Odds ratio: 9.995, P = 0.005).
Conclusions:
- IMPV is present in gallbladder adenocarcinoma and associated with aggressive behavior.
- IMPV is a significant risk factor for lymph node metastasis in gallbladder cancer.
- IMPV is a valuable predictor of regional lymph node metastasis in gallbladder adenocarcinoma.
