Negative pathology after endoscopic resection of gastric epithelial neoplasms: importance of pit dysplasia

Endoscopic resection (ER) is a well-established treatment modality for gastric epithelial neoplasm. However, there is a discrepancy between forceps biopsy and ER specimen pathology, including a negative pathologic diagnosis (NPD) after ER. It has been suggested that pit dysplasia (PD) is a subtype of gastric dysplasia, and the aim of this study was to assess the significance of PD in cases with NPD after ER for early gastric neoplasms. After ER, 29 NPD lesions that had an associated pretreatment forceps biopsy specimen, were correctly targeted during ER, and had no cautery artifact on the resected specimen were included in this study. Sixteen lesions showed PD and 13 had no neoplastic pathology. The initial pretreatment forceps biopsy diagnoses of 29 NPD lesions were low-grade dysplasia (LGD) in 17 lesions, high-grade dysplasia (HGD) in seven lesions, and adenocarcinoma in five lesions, which after review were revised to PD in 19 lesions, LGD in four lesions, adenocarcinoma in two lesions, and no neoplastic pathology in four lesions. Overall, nine lesions (31%) were small enough to be removed by forceps biopsy, four NPD lesions (14%) were initially misinterpreted as neoplastic lesions, and 16 PD lesions (55%) were misinterpreted as NPD lesions on ER slides. Approximately half of the lesions initially diagnosed as LGD or HGD were subsequently classified as PD. Therefore, including PD as a subtype of gastric dysplasia could reduce the diagnostic discrepancy between initial forceps biopsy and ER specimens.