Evaluation of Prognostic Significance of Micropapillary Component in Colorectal Carcinoma

Abstract

The aims of the study are to reclassify colorectal carcinomas based on presence or absence of a micropapillary component and evaluate its prognostic significance. We studied 100 cases of colorectal carcinoma with 5-year follow-up information at Department of Pathology, Kasturba Medical College and Hospital Manipal, India. H&E sections from 2 blocks of the main tumor were studied for a micropapillary component along with other parameters like histologic grade, TNM stage, Astler Colles stage, peritumoral lymphocytic infiltration, and tumor budding. The Fisher exact test was used for statistical analysis. In 43% of the colorectal carcinomas, there was a micropapillary component. High-grade morphology (35% vs 25%), increased lymphovascular invasion (98% vs 42%), perineural invasion (30% vs 16%), tumor budding (81% vs 42%), lymph node metastasis (56% vs 33%) was higher and predicted more frequent lymph node metastasis in colorectal carcinoma with micropapillary component as compared with colorectal carcinoma without micropapillary component and was statistically significant. However, there was no statistically significant difference between the 2 groups with respect to age, sex, anatomic location, depth of infiltration, peritumoral lymphocytic infiltration, histologic grade, perineural invasion, and distant metastasis. Colorectal carcinomas with micropapillary component had a shorter survival time in TNM sage I and II, more lymph node metastasis and distant metastasis, lower differentiation status, and more aggressive behavior. As diagnosis of micropapillary component is simple, reproducible, and cost-effective, it would be a valuable parameter in identifying high-risk groups in TNM stage I and II. Limitations of the study were sampling error and sample size. Kaplan-Meier survival curves could not be obtained as none of the patients died during the follow-up period.