Diagnosis of borderline adenomas of the stomach by endoscopic mucosal resection

Background and Study Aims: The correct histological diagnosis of gastric borderline adenomas is often difficult, especially in excluding malignancy, since the usual diagnostic methods, such as radiography and histological examination of forceps biopsy specimens, are of limited accuracy. The aim of this study was to retrospectively analyze the value of endoscopic mucosal resection in establishing the correct diagnosis of boderline adenomas. Patients and Methods: Fifty patients diagnosed as having borderline adenomas of the stomach were included in the study, None of the tumors had a conclusive diagnosis of carcinoma on endoscopic biopsy. Following endoscopic mucosal resection, the histological results of biopsy and resected specimens were analyzed. Results: Fourteen borderline adenomas were finally diagnosed as containing early gastric cancer type IIa (well-differentiated tubular adenocarcinoma) after endoscopic mucosal resection, of the remaining 36 tubular adenomas, six represented mild dysplasia, 24 moderate dysplasia, and six severe dysplasia. Most parts of the 14 adenomas containing early gastic cancers had regions of structural atypia, and cellular atypia was moderate in all. Seven of 14 cancers were completely resected, all patients being tumor-free after a follow-up of 33-61 months. Conclusions: These results suggest that diagnosing borderline adenoma on the basis of radiographic and endoscopic-bioptic findings is generally unreliable, because biopsy specimens may not be representative of the entire lesion. Borderline adenomas of the stomach should be completely resected by endoscopic mucosal resection to obtain a final diagnosis and - depending on the size and type of the lesion - possibly also definitive treatment.