Cerebral Thromboembolism after Lobectomy for Lung Cancer: Pathological Diagnosis and Mechanism of Thrombus Formation

Figures

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  Figure 1. The coagulation pathway and its relationship to the fibrinolytic system (modification of reference [22]). In the coagulation cascade, the activation of factor X is initiated by both extrinsic and intrinsic pathways, which converge in the formation of a fibrin plug, which is degraded by plasmin in the fibrinolytic system. Activated factors are indicated with a lowercase “a”.

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  Figure 2. Scheme of thrombosis triggered by Virchow’s triad (modification of reference 22). Thrombosis is caused by endothelial injury, abnormal blood flow (e.g., stasis and turbulence of blood flow), and/or hypercoagulability. These three factors interact with each other. AF, atrial fibrillation; DIC, disseminated intravascular coagulopathy; HIT, heparin-induced thrombocytopenia.

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  Figure 3. Mechanism of cerebral embolism after lobectomy for lung cancer. Thrombi are formed via two distinct pathways: atrial fibrillation (AF) and pulmonary vein stump (PVS). Hypercoagulability induced by lung cancer may induce thrombus formation via these two pathways.

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  Figure 4. Examples of thrombus morphology (hematoxylin and eosin staining). A thrombus due to disseminated intravascular coagulopathy is composed of dense fibrin (A, bar = 125 µm). A coronary atherogenic thrombus contains many atheromas with fibrin deposits accompanied by abundant neutrophils (black arrowheads) (B, bar = 250 µm). A cerebral atherogenic embolic thrombus contains two components (C, bar = 625 µm; D, bar = 125 µm, separated by a dotted line): an erythrocyte-rich component (D, red arrowheads) and an atheroma including foamy macrophages (D, blue arrowheads).

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  Figure 5. Examples of thrombus morphology (hematoxylin and eosin staining). A thrombus due to thrombophlebitis (A and B), which contains an increased number of erythrocytes, accompanied by a relatively thick fibrinous material (A, bar = 625 µm) and an increased number of neutrophils that infiltrate the venous walls (B, bar = 125 µm). A thrombus that caused a pulmonary thromboembolism resulting from deep vein thrombosis (C and D). This type of thrombus is characterized by abundant erythrocytes and mesh-like fibrin (C, bar = 625 µm; D, bar = 125 µm). A cardiogenic thrombus due to atrial fibrillation is composed of two components (E, bar = 625 µm): a relatively dense fibrinous material, scattered neutrophils (black arrowheads), and a small number of erythrocytes (F, bar = 125 µm); and abundant erythrocytes admixed with the former component (E).

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  Figure 6. Morphology of a cerebral thromboembolus formed within the pulmonary vein stump (PVS) after pulmonary lobectomy for lung cancer (hematoxylin and eosin staining). This type of thrombus is composed of two components (A, bar = 625 µm): a laminar fibrinous component (blue arrowheads) and an erythrocyte-rich component accompanied by a thin mesh-like fibrin network (red arrowheads). The former component is composed of laminar fibrin along with abundant neutrophils (mimicking purulent exudate) and abundant erythrocytes (B, bar = 125 µm).