Treatment for gastric ‘indefinite for neoplasm/dysplasia’ lesions based on predictive factors

Figure 1 Flow chart of study inclusion and exclusion, and enrollment of 461 lesions with ‘indefinite for neoplasm/dysplasia’ status. The final diagnoses are shown in the gray boxes. IFND: Indefinite for neoplasm/dysplasia; ER: Endoscopic resection; Diff: Differentiated carcinoma; Undiff: Undifferentiated carcinoma.

Figure 2 Representative cases of undifferentiated carcinoma. Flat lesions with color change (A-C) and fold change with ulcerations (D-F) are shown at endoscopy. G: The case in panel A shows a few tumor cells (magnified in the inlet) in the endoscopic biopsy specimen (black arrow). H: The resected specimen shows poorly differentiated tubular adenocarcinoma with a very small tumor size (0.7 cm × 0.6 cm). I: The case in panel B shows a few tumor cells in the endoscopic biopsy specimen (black arrow). J: The resected specimen shows mixed signet ring cell carcinoma and poorly differentiated tubular adenocarcinoma with a very small tumor size (0.6 cm × 0.4 cm). K: The case in panel e shows a few tumor cells as squeezing artifact-like clusters in the endoscopic biopsy specimen (black arrow). L: The resected specimen shows mixed poorly differentiated (dotted arrow) and well-differentiated (red arrow) tubular adenocarcinoma.

Figure 3 Representative images of Indefinite for neoplasm/dysplasia lesions with repeated diagnoses (from regenerating atypia to atypical epithelium), which were finally confirmed as well-differentiated adenocarcinoma at endoscopic submucosal dissection. A: A lesion with mucosal irregularity and hyperemia is seen on the lesser curvature side of the prepylorus (indicated by arrows). B: After endoscopic submucosal dissection, the yellow line illustrates the boundary of the lesion confirmed in the pathology, measuring 1.7 cm × 1.0 cm. C: Regenerating atypia at the initial forceps biopsy shows focal glandular crowding with a basally-located, hyperchromatic nucleus. Glandular transition to the surrounding mucosa is observed. D: Atypical epithelium at follow-up biopsy after 598 d shows more crowded and tortuous glands. A few glands showed irregular distention. However, the hyperchromatic but basally-located nuclear atypia was mild. E: Endoscopic submucosal dissection was performed 2249 d later. It revealed well-differentiated adenocarcinoma. The low-power view shows surface maturation. F: The neoplastic tubules were prominent from the mid-portion of the tubular pit to the bottom of the gland; G: They form crowded, back-to-back, branched, and tortuous glands with disordered nuclei; H: Surface atypia is less prominent and mild nuclear atypia is observed. IFND: Indefinite for neoplasm/dysplasia.

Figure 4 The guideline established in our institute for ‘indefinite for neoplasm/dysplasia’ in gastric biopsy. Bx: Biopsy; IFND: Indefinite for neoplasm/dysplasia.