Lines of Zahn

Lines of Zahn are a characteristic of thrombi that appear particularly when formed in the heart or aorta. They have visible and microscopic alternating layers (laminations) of platelets mixed with fibrin, which appear lighter, and darker layers of red blood cells. Their presence implies thrombosis at a site of rapid blood flow that happened before death. In veins or smaller arteries, where flow is not as constant, they are less apparent.

They are named after German-Swiss pathologist Friedrich Wilhelm Zahn.

Recent pulmonary thromboembolus exhibiting prominent lines of Zahn. The pale areas consist of fibrin and platelets; the red areas consist of erythrocytes.

Low magnification micrograph showing laminations in a thrombus in a fatal pulmonary embolism. H&E stain.

Intermediate magnification micrograph showing laminations in a thrombus in a fatal pulmonary embolism. H&E stain.

High magnification micrograph showing laminations in a thrombus in a fatal pulmonary embolism. H&E stain.

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