USMLE Step 2 CK: Colonic Ischemia and Polyp Malignancy
Risk Questions with Answers (100% Correct Answers)
What complication did the 64-year-old male experience after coronary artery bypass surgery?
—Answer: Abdominal pain followed by bloody diarrhea.
What is the most likely diagnosis for the patient with abdominal pain and bloody diarrhea after
surgery? —Answer: Ischemic colitis.
Which area of the colon is most commonly involved in ischemic colitis? —Answer: The splenic
flexure.
Why is the splenic flexure particularly vulnerable to ischemic colitis? —Answer: It is supplied
by end arteries and is a watershed area between the superior and inferior mesenteric arteries.
What are common symptoms of ischemic colitis? —Answer: Acute onset of lower abdominal
pain followed by bloody diarrhea, fever, nausea, vomiting, and leukocytosis.
What laboratory finding can indicate ischemic colitis? —Answer: Elevated lactic acid levels.
What is the significance of the recto-sigmoid junction in ischemic colitis? —Answer: It is
another watershed area supplied by terminal branches of the inferior mesenteric artery.
What is the most common type of polyp found in the colon? —Answer: Adenoma.
Which type of polyp is considered the most premalignant? —Answer: Villous adenoma.
What are the three types of adenomatous polyps? —Answer: Tubular adenoma, tubulovillous
adenoma, and villous adenoma.
What is the risk of malignancy associated with polyps larger than 2.5 cm? —Answer:
Substantial risk (10% chance of containing invasive cancer).
What is the likelihood of an adenomatous polyp progressing to cancer? —Answer: Less than
1% for most adenomatous polyps.
© 2025 All rights reserved
Risk Questions with Answers (100% Correct Answers)
What complication did the 64-year-old male experience after coronary artery bypass surgery?
—Answer: Abdominal pain followed by bloody diarrhea.
What is the most likely diagnosis for the patient with abdominal pain and bloody diarrhea after
surgery? —Answer: Ischemic colitis.
Which area of the colon is most commonly involved in ischemic colitis? —Answer: The splenic
flexure.
Why is the splenic flexure particularly vulnerable to ischemic colitis? —Answer: It is supplied
by end arteries and is a watershed area between the superior and inferior mesenteric arteries.
What are common symptoms of ischemic colitis? —Answer: Acute onset of lower abdominal
pain followed by bloody diarrhea, fever, nausea, vomiting, and leukocytosis.
What laboratory finding can indicate ischemic colitis? —Answer: Elevated lactic acid levels.
What is the significance of the recto-sigmoid junction in ischemic colitis? —Answer: It is
another watershed area supplied by terminal branches of the inferior mesenteric artery.
What is the most common type of polyp found in the colon? —Answer: Adenoma.
Which type of polyp is considered the most premalignant? —Answer: Villous adenoma.
What are the three types of adenomatous polyps? —Answer: Tubular adenoma, tubulovillous
adenoma, and villous adenoma.
What is the risk of malignancy associated with polyps larger than 2.5 cm? —Answer:
Substantial risk (10% chance of containing invasive cancer).
What is the likelihood of an adenomatous polyp progressing to cancer? —Answer: Less than
1% for most adenomatous polyps.
© 2025 All rights reserved
