A 63-year-old man undergoes a screening colonoscopy and is found to have a polyp in his sigmoid colon. Which type of polyp is most associated with malignancy?
**Core Concept**
Polyps in the colon can be classified into different types based on their histological characteristics, and some types are more likely to be associated with malignancy than others. The most relevant classification system is the WHO classification of colorectal polyps, which categorizes them into adenomatous, serrated, and hyperplastic polyps.
**Why the Correct Answer is Right**
Hyperplastic polyps are generally considered to be non-neoplastic and are not typically associated with malignancy. However, serrated polyps, particularly sessile serrated adenomas (SSA), are known to be a precursor to colorectal cancer. SSA polyps are characterized by a serrated architecture and are often found in the right colon. They have a higher risk of harboring genetic mutations that can lead to cancer. Among the options, serrated polyps are the most associated with malignancy.
**Why Each Wrong Option is Incorrect**
**Option A:** Adenomatous polyps are indeed associated with malignancy, but they are not the most associated type. Adenomatous polyps are a precursor to colorectal cancer, and their risk of malignancy increases with their size and degree of dysplasia. However, serrated polyps are more likely to be associated with right-sided colon cancer.
**Option B:** Hyperplastic polyps are generally considered to be non-neoplastic and are not typically associated with malignancy.
**Option D:** No option was provided for this choice.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that serrated polyps, particularly SSA, are a significant risk factor for colorectal cancer, and their detection and removal are crucial for preventing cancer.
**Correct Answer: C. Serrated polyps.**