Effect of mucosal thickening near gastric carcinoma on the endoscopic diagnosis of malignancy.

Gastric mucosal thickening of variable degree occurs in the vicinity of gastric carcinomas and is possibly related to simultaneous tumor expression of epidermal growth factor and its receptor. Seventeen cases in which both endoscopic biopsy and subsequent resection for gastric carcinoma had been performed were studied to see if putative tumor-related mucosal thickening had an effect on endoscopic biopsy sensitivity. Biopsy fragment positivity rate was greater in cases with exophytic, protruding tumor masses (46.8 +/- 8.5%) than in all other cases (17.0 +/- 4.7%; P = 0.02). Thickness of nontumorous mucosa adjacent to carcinomas did not significantly affect the biopsy fragment positivity rate in cases with exophytic masses ("thin" subgroup, 51.0 +/- 16.2%; "thick" subgroup, 44.0 +/- 10.8%; P = 0.7) but did reduce the positivity rate significantly (P = 0.05) in ulcerative or infiltrative tumors without exophytic components ("thin" subgroup, 23.3 +/- 4.1%; "thick" subgroup, 8.4 +/- 2.1%). This reduction in biopsy sensitivity related to mucosal thickening occurring adjacent to nonprotuberant lesions may explain, at least in part, the variable rates of positive biopsies observed with gastric cancers.