**Question:** In which of the following locations would you least expect to find significant atherosclerotic lesions in a patient with risk factors of smoking, hypertension, diabetes mellitus, and serum cholesterol level of 280 mg/dl?

**Core Concept:** Atherosclerosis is a progressive and chronic inflammatory disease of the arterial walls, characterized by the accumulation of lipids and cellular elements, leading to the formation of plaques that may cause narrowing and hardening of the arteries. The risk factors involved in this process include smoking, hypertension, diabetes mellitus, and high serum cholesterol levels.

**Why the Correct Answer is Right:** The correct answer is **D.** Atherosclerosis typically occurs in the large elastic arteries, particularly the coronary, cerebral, and peripheral arteries. Involvement of the peripheral arteries (option A) is common, while coronary artery involvement (option B) is more common in patients with diabetes and hypertension. Atherosclerosis in the cerebral arteries is also common (option C). However, the least expected location is the renal arteries (option D), as they are relatively protected by the kidneys' ability to compensate for reduced blood flow.

**Why Each Wrong Option is Incorrect:**

A. Peripheral arteries: Smoking and high serum cholesterol levels increase the risk of atherosclerosis in peripheral arteries.
B. Coronary arteries: Coronary arteries are more commonly affected in patients with diabetes and hypertension due to increased oxidative stress and inflammation.
C. Cerebral arteries: Atherosclerosis in cerebral arteries is common in patients with diabetes and hypertension, leading to cerebrovascular disease.
D. Renal arteries: Renal arteries are relatively protected by the kidneys' ability to compensate for reduced blood flow.

**Clinical Pearl:** The understanding of atherosclerosis targeting specific arteries helps in identifying the presenting symptoms and complications of the disease. For example, renal artery stenosis (option D) may present with hypertension, while coronary artery involvement (option B) can cause angina and myocardial infarction.

**Correct Answer:** D. Renal arteries