Resumen
Esophageal and esophago-gastric junction adenocarcinomas (EA/EGJAs) are a heterogeneous group of cancers. Stage is the most important prognostic factor, while morphology, determined by histologic analysis, has up until now played a minor role. Even new molecular classifications (which should be based on accurate histologic assessment) are a long way off from being used in day to day practice. The reassessment of nearly 300 EA/EGJAs enabled us to re-evaluate morphology and identify a two-tiered grading approach in glandular adenocarcinomas (80%) based on a cut off of 6% of poorly differentiated components (well differentiated versus poorly differentiated). Furthermore, rare, but prognostically significant, variants were recognized with an in-depth morphologic description. On this basis, two morphologic risk groups (lower risk and higher risk) were identified, adding significant prognostic value to the stage. The accurate morphologic description of EA/EGJAs must be a prerequisite for a better understanding of prognosis, molecular events, and response to treatment.