Irregular focal thickening of walls of medium and large muscular arteries is characteristic of which condition?

• A. Vasculitis
• B. Atherosclerosis
• C. Fibromuscular dysplasia
• D. Arteriovenous malformation

Answer: (C)

Fibromuscular dysplasia. This condition produces noninflammatory, nonatherosclerotic irregular thickening of the media in medium to large arteries, leading to alternating stenosis and dilation that gives a beaded, irregular wall appearance on imaging. It most classically affects renal and carotid arteries and tends to occur in younger to middle-aged women, often presenting with hypertension or neurovascular symptoms. This pattern distinguishes it from vasculitis (inflammation-driven wall changes), atherosclerosis (lipid-rich plaque with aging and risk factors), and arteriovenous malformation (abnormal vessel connections rather than wall thickening).