A 58-year-old man presents with acute painless loss of vision in the superior temporal quadrant of his right eye. Fundoscopy reveals sectoral retinal whitening **A** with a sharply demarcated edge at the watershed zone. A yellow-orange refractile deposit is visible at an arteriolar bifurcation. Which of the following is the most likely source of the embolus in this patient?

Question

Accepted Answer

A. Carotid atherosclerotic plaque (Hollenhorst plaque). ## Why Hollenhorst plaque (carotid atherosclerotic plaque) is right

The sectoral retinal whitening **A** in this patient represents acute ischemic edema of the inner retinal layers supplied by the occluded branch retinal arteriole. The yellow-orange refractile appearance of the embolus at the bifurcation is pathognomonic for a **Hollenhorst plaque** — cholesterol crystals derived from carotid atherosclerotic plaques. This is the most common embolic source in branch retinal artery occlusion (BRAO), accounting for the majority of cases. The presence of this characteristic appearance mandates urgent carotid duplex ultrasonography to assess for hemodynamically significant stenosis (>50%) amenable to endarterectomy or stenting, as BRAO is a stroke equivalent and carries elevated 5-year stroke risk (AAO BCSC Retina/Vitreous; AHA Stroke Guidelines).

## Why each distractor is wrong

- **Calcific aortic valve disease**: Calcific emboli appear as chalky-white, opaque deposits, not yellow-orange refractile plaques. While they do cause BRAO, the clinical appearance described here is inconsistent with calcific emboli.
- **Fibrin-platelet thrombus from left ventricular wall**: These emboli appear as dull white, elongated plugs rather than refractile yellow-orange deposits. They are associated with acute myocardial infarction or dilated cardiomyopathy, not the appearance seen here.
- **Paradoxical embolism through a patent foramen ovale**: PFO-related emboli are typically venous thrombi that cross the septum; they do not produce the characteristic yellow-orange refractile appearance of a Hollenhorst plaque and are less common in BRAO than carotid disease.

**High-Yield:** Hollenhorst plaque = yellow-orange refractile cholesterol crystals at arteriolar bifurcation = carotid atheroma = urgent carotid imaging.

[cite: AAO Retina/Vitreous BCSC; AHA Stroke Guidelines]

Answer

B. Paradoxical embolism through a patent foramen ovale

Answer

C. Calcific aortic valve disease

Answer

D. Fibrin-platelet thrombus from left ventricular wall

Explanation

Why Hollenhorst plaque (carotid atherosclerotic plaque) is right

Why each distractor is wrong

Practice similar questions