American Board of Internal Medicine (ABIM) Certification Practice Exam

What factors indicate that invasive adenocarcinoma arising in a polyp can be managed by endoscopic polypectomy alone?

1. Effective barium enema results

2. Removal en bloc, minimal invasion, no adverse histologic features, and clear margins

3. Presence of dysplastic cells

4. Positive margins with clear lymph nodes

The correct answer is: Removal en bloc, minimal invasion, no adverse histologic features, and clear margins

Invasive adenocarcinoma arising in a polyp can often be managed by endoscopic polypectomy alone when specific criteria are met. The key indicators include the removal of the polyp en bloc, minimal invasion into the submucosa, absence of adverse histologic features, and the presence of clear margins following the excision. When a polyp is removed en bloc, it means that the entire lesion, along with its surrounding tissue, has been excised in a single piece, which allows for a comprehensive evaluation of the margins and the underlying pathology. Minimal invasion signifies that the cancer has not penetrated deeply into the submucosal layers, reducing the risk of metastasis and local recurrence. The absence of adverse histologic features—such as high-grade dysplasia, invasive growth patterns, or lymphovascular invasion—further supports the decision for endoscopic management. Clear margins indicate that the cancer has not been found at the edges of the resected tissue, suggesting that the excision has successfully removed all cancerous cells, thereby minimizing the chances for subsequent complications or recurrences. In summary, when a polyp detects invasive adenocarcinoma, successful endoscopic treatment hinges on these characteristics, providing a strong basis for considering