A 65-year-old man presented with an episode of syncope. He said he felt dizzy during defecation and noticed gross bleeding in the pan. Fecal occult blood test done 3 months ago as a part of routine screening for colon cancer was negative. There is no history of recent weight loss. What is the likely colonoscopic finding?

**Core Concept**
The patient's symptoms of syncope and gross bleeding during defecation, in conjunction with a previously negative fecal occult blood test, suggest a potential lower gastrointestinal (GI) bleed. The likely cause is a vascular lesion in the colon, which could be a source of significant bleeding.

**Why the Correct Answer is Right**
The most common vascular lesion in the colon is a **diverticulum**, particularly a **diverticulosis**. Diverticula are outpouchings of the colonic wall, often found in the sigmoid colon. They are more common in older adults, especially those with a low-fiber diet. The presence of gross bleeding during defecation and a previously negative fecal occult blood test suggests that the bleeding is intermittent, which is consistent with a diverticular bleed. The bleeding can be due to erosion of a diverticulum into a nearby blood vessel.

**Why Each Wrong Option is Incorrect**
* **Option A:** **Angiodysplasia** is a vascular lesion of the colon, but it is more common in older adults and typically presents with occult bleeding rather than gross bleeding.
* **Option B:** **Colon cancer** is less likely given the negative fecal occult blood test and the absence of weight loss.
* **Option C:** **Inflammatory bowel disease (IBD)**, such as ulcerative colitis or Crohn's disease, can cause bleeding, but the presentation would typically include other symptoms like diarrhea, abdominal pain, and weight loss.

**Clinical Pearl / High-Yield Fact**
Diverticula are more common in the sigmoid colon due to the high pressure and low compliance of this segment of the colon.

**Correct Answer:** D. Diverticulosis.

✓ Correct Answer: D. Dilated mucosal and submucosal veins in the colon