Distinction of Intestinal and Diffuse Types of Gastric Adenocarcinoma on Brush Cytology

Objective: To distinguish between the intestinal and diffuse types of gastric adenocarcinoma on brush cytology (BC). Study Design: Brushing smears and biopsy samples obtained at endoscopic examination from 32 patients with clinically or radiologically suspected gastric malignancy were included in the study. Cytologic smears were examined by 2 cytopathologists, using predetermined criteria to arrive at a consensus diagnosis. A meticulous attempt was made to distinguish between the 2 types of gastric adenocarcinoma. Cytologic diagnoses were correlated with the histologic diagnoses. Results: Twenty-one cases (65.6%) were concordant between BC and endoscopic biopsy (EB) with respect to sub-typing. Two (6.2%) cases reported as `poorly differentiated adenocarcinoma' on BC turned out to be `diffuse type'. Three cases (9.4%) reported as `diffuse type' on BC were `intestinal type' on EB. Two of these discordant cases had intestinal metaplasia on BC, which should have suggested `intestinal type' of adenocarcinoma on BC. Three cases (9.4%) were false positive. On review, 2 of these false-positive cases showed cytologically convincing malignant cells, the third case was misinterpreted as diffuse type of adenocarcinoma due to reactive glandular cells entangled in the mucoid background. Three (9.4%) EB were non-representative with only superficial mucosa; BC diagnosis in these 3 cases was intestinal type of adenocarcinoma. Conclusion: Although, overlapping cytomorphology between the intestinal and diffuse types of gastric adenocarcinoma can cause diagnostic problem; with a meticulous cytomorphologic approach, it is possible to accurately distinguish between the 2 types in a considerable number of cases. Copyright (C) 2011 S. Karger AG, Basel