What type of intestinal polyp (Intestinal Obstruction, IO) is most likely to cause intussusception of the small bowel in a middle-aged patient with a history of intestinal polyps?

Peutz-Jeghers Syndrome Polyps Are the Most Likely Cause

In a middle-aged patient presenting with small bowel intussusception and a history of intestinal polyps, Peutz-Jeghers syndrome (PJS) hamartomatous polyps are the most likely culprit, as they are specifically known to cause intussusception in the small bowel, particularly in adults who have survived childhood complications.

Why Peutz-Jeghers Syndrome Polyps

Characteristic Association with Small Bowel Intussusception

• PJS polyps are the classic cause of small bowel intussusception, with a cumulative intussusception risk of 50-68% during childhood and continuing into adulthood 1.
• The median age of first intussusception is 10-16 years, but symptoms often arise between ages 10-30 years, with intussusception occurring in 47% of patients, primarily in the small intestine (95% of cases) 1.
• Small bowel polyps >1.5-2 cm in PJS are specifically identified as the size threshold that causes intussusception, with a median polyp size of 35 mm (15-60 mm) in confirmed intussusception cases 1.

Histopathologic Features

• PJS polyps are true hamartomas with a characteristic frond-like structure, branching framework of connective tissue and smooth muscle, and arborizing smooth muscle extending into the polyp 1.
• They occur most numerously in the small intestine (64% of affected individuals), making them the predominant small bowel polyp type associated with intussusception 1.

Why Not the Other Options

Juvenile Polyps (Option A)

• Juvenile polyposis syndrome (JPS) polyps are hamartomatous but predominantly affect the colon and rectum, not the small bowel 1.
• The diagnostic criteria for JPS require >5 juvenile polyps in the colon/rectum or juvenile polyps in other GI tract parts, but small bowel involvement causing intussusception is not a characteristic feature 1.

Cowden Syndrome (Option B)

• While Cowden syndrome involves hamartomatous polyps, it is not specifically associated with small bowel intussusception in the literature provided.
• The evidence does not support Cowden syndrome polyps as a common cause of small bowel obstruction via intussusception.

Lipoma (Option C)

• Lipomas are benign small bowel lesions that can cause obstruction, but they are not polyps in the traditional sense 2.
• While lipomas can serve as lead points for intussusception, they are not associated with a "history of intestinal polyps" as described in the question, which implies a polyposis syndrome.

FAP (Option D)

• Familial adenomatous polyposis (FAP) involves adenomatous polyps that predominantly affect the colon 1.
• FAP polyps are not characteristically associated with small bowel intussusception; the primary concern in FAP is colorectal cancer risk from adenomatous transformation 1.

Clinical Pitfalls

• Do not delay surgical intervention in adult intussusception, as delay beyond 48 hours significantly increases mortality 3.
• In PJS patients presenting with acute abdominal pain, intussusception should be the primary consideration, requiring urgent imaging (CT scan) and surgical consultation 1, 3.
• The presence of mucocutaneous pigmentation (particularly at the vermillion border of lips) may fade with age in adults, so its absence does not exclude PJS 1.

Answer: The polyp type is most consistent with Peutz-Jeghers syndrome hamartomatous polyps, though this is not explicitly listed as option "a" (Juvenile). If forced to choose from the given options and "Juvenile" refers to hamartomatous polyps in general, this would be the closest answer, but PJS is the specific syndrome diagnosis.