Clinical characterization of gastric lesions initially diagnosed as low-grade adenomas on forceps biopsy

Aim: The aim of this study was to elucidate characteristics of gastric lesions that are initially diagnosed as low-grade adenomas and to establish appropriate treatment.

Methods: We retrospectively reviewed 231 lesions initially diagnosed as gastric adenomas. All forceps biopsy samples were histologically diagnosed as category 3 low-grade adenomas according to the revised Vienna Classification. All patients underwent endoscopic resection with endoscopic findings and post-resection diagnoses evaluated subsequently.

Results: Sixty-three lesions were initially diagnosed as depressed adenomas, and 168 lesions were diagnosed as protruding adenomas. The depressed lesions were significantly smaller (11.6 ± 5.0 mm) than the protruding lesions (17.0 ± 10.8 mm) (P < 0.001). Diagnoses reclassified to category 4 mucosal high-grade neoplasia (i.e. high-grade adenoma, adenocarcinoma in adenoma and adenocarcinoma) were more frequent among depressed lesions (52.4%) than among protruding lesions (31.0%) (P = 0.004). Multivariate analysis of all 231 lesions showed that lesion size larger than 20 mm (P < 0.001) and depressed appearance (including central depression) (P < 0.001) were significant independent factors suggesting cancer. For the 168 protruding lesions, lesion size larger than 20 mm (P < 0.001) and central depression (P < 0.001) were significant independent factors suggesting cancer. For the 63 depressed lesions, lesion size larger than 15 mm (P = 0.016) and a moth-eaten appearance (P = 0.017) were significant independent factors in the pre-treatment diagnosis of cancer.

Conclusions: Adenocarcinoma lesions were often found in depressed lesions and protruding lesions with central depression. Endoscopic resection for total biopsy is recommended, even if forceps biopsy indicates low-grade adenoma, as pre-treatment biopsy may be inadequate for an accurate histological diagnosis.