A 58-year-old man with untreated tertiary syphilis dies of heart failure. Autopsy shows a markedly dilated ascending aortic aneurysm with a wrinkled, scarred intima described as tree bark appearance. The underlying process responsible for this pattern of aneurysm formation is:

• A Cystic medial degeneration of the ascending aortic media
• B Obliterative endarteritis of the vasa vasorum with medial ischemia ✓
• C Transmural atherosclerotic replacement of the media
• D Granulomatous destruction of the adventitia by gummas

Explanation

Syphilitic aortitis involves the ascending aorta because Treponema pallidum infects the vasa vasorum, producing obliterative endarteritis with plasma cell infiltrates. Ischemic injury to the media causes loss of smooth muscle and elastic fibers, aneurysmal dilation, and calcification with the characteristic tree bark intima. Atherosclerotic aneurysms favor the abdominal aorta below the renal arteries, which distinguishes that distractor from the thoracic location typical of syphilis.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.