American Board of Internal Medicine (ABIM) Certification Practice Exam

Which adverse histologic features make polypectomy potentially insufficient for invasive adenocarcinoma?

1. Pi-3-kinase mutation

2. Lymphovascular invasion

3. High-grade dysplasia

4. Adenomatous histology

The correct answer is: Lymphovascular invasion

Lymphovascular invasion is a critical histologic feature that indicates a greater likelihood of cancer spread. In the context of invasive adenocarcinoma detected in a polyp, the presence of lymphovascular invasion suggests that cancer cells may have penetrated beyond the confines of the polyp and potentially reached nearby lymphatic vessels or blood vessels. This finding raises concern about the adequacy of a simple polypectomy as a treatment, as it implies a risk of metastasis, making additional interventions, such as surgical resection, necessary to ensure all cancerous tissue is removed and to prevent recurrence. Invasive adenocarcinoma's behavior can significantly change based on these histological findings. Features like high-grade dysplasia indicate severe precancerous changes but do not definitively signal invasion. Adenomatous histology signifies a benign type of growth that may precede cancer but does not reflect the invasive nature of cancer itself. Pi-3-kinase mutations are relevant to cancer progression but do not directly correlate with the adequacy of a polypectomy. Thus, lymphovascular invasion directly influences the treatment approach following polypectomy, as it indicates a need for more aggressive surgical management to reduce the risk of adverse outcomes related to cancer spread.