This study aimed to characterize the clinicopathological features of invasive micropapillary carcinoma (IMPC) of the stomach.Methods and results:
Seventeen cases of gastric IMPC were identified from histological reviews of 1178 consecutive cases. IMPC components occupied 10–90% of the entire tumours. Fifteen tumours showed invasion into the muscularis propria or deeper, whereas two tumours were limited to the submucosa. All 17 cases were associated with tubular or papillary adenocarcinoma. Lymphatic and venous invasion were identified more frequently in cases with IMPC components than in those without (P = 0.0023 and P = 0.0009, respectively). Nodal metastases were identified in 14 of 17 (82%) cases with IMPC components, whereas they were detected in 540 of 1161 (47%) cases with no IMPC components (P = 0.0053). Multivariate analysis demonstrated that the presence of IMPC was an independent predictor of nodal metastasis.Conclusions:
Conservative treatments, such as endoscopic resection, should not be used for gastric carcinoma with IMPC components, as these cases are associated with a high propensity for lymphovascular invasion and nodal metastasis.