Medullary-Type Poorly Differentiated Adenocarcinoma of the Large Bowel: A Distinct Clinicopathologic Entity Characterized by Microsatellite Instability and Improved Survival

摘要: PURPOSE: Recent studies suggest the existence of a distinct class poorly differentiated large bowel adenocarcinomas, usually termed medullary-type adenocarcinomas (MTAs). The aim present study was to accurately define clinical, histopathologic, biologic, and genetic features this tumor type. MATERIALS AND METHODS: Among 1,265 surgically resected sporadic colorectal carcinomas, 45 MTAs were identified on basis following criteria: predominantly solid growth pattern (at least 70% area) lack marked nuclear pleomorphism. clinicopathologic, characteristics compared with those series 457 common glandular adenocarcinomas. RESULTS: significantly different clinicopathologic proximal location, size, invasion into adjacent organs, expanding growth, low incidence distant metastases, more frequent conspicuous peritumoral lymphocytic infiltration, Crohn's-like lympho...