Pathology Colloquium Slides PDF

1. Post-Myocardial Infarction (MI) (Late Stage/Healing MI) ​ Granulation tissue formation (fibroblasts, new capillaries, macrophages) ​ Collagen deposition (fibrosis) replacing necrotic myocardium (picture 3) ​ Reduced inflammatory infiltrate ​ Loss of normal myocardial architect...

1. Post-Myocardial Infarction (MI) (Late Stage/Healing MI) ​ Granulation tissue formation (fibroblasts, new capillaries, macrophages) ​ Collagen deposition (fibrosis) replacing necrotic myocardium (picture 3) ​ Reduced inflammatory infiltrate ​ Loss of normal myocardial architecture ​ Thinning of ventricular wall (in chronic cases) 2. Recent Myocardial Infarction (Acute MI, within 1-5 days) ​ Coagulative necrosis of cardiac myocytes (preserved cell outlines but loss of nuclei) ​ Wavy myocardial fibers due to contraction band necrosis (3rd picture) ​ Early infiltration by neutrophils (pictures 1 and 2) ​ Interstitial edema and hemorrhage ​ Loss of cross-striations in muscle fibers 3. Splenic White Infarct ​ Wedge-shaped area of coagulative necrosis ​ Pale, eosinophilic necrotic tissue with ghost outlines of cells (picture 2) ​ Peripheral zone of inflammatory infiltration (neutrophils, macrophages) …picture 3 ​ Possible hemorrhagic border due to congestion of adjacent tissues ( …picture 1, red part) ​ Loss of normal splenic architecture 4. Hemorrhagic Foci of the brain ​ Red blood cell extravasation into tissues ​ Macrophages with hemosiderin-laden cytoplasm (if chronic) ​ Vascular congestion and dilation ​ Edema and inflammatory infiltrate in adjacent tissues ​ Pyramidal cells (2nd picture) ​ Blood vessel with possible thrombosis and surrounding hemorrhage —3rd picture(thrombosed vessel in a hemorrhagic infarct) …pale eosinophilic material in the middle could be fibrin deposits within a thrombus, commonly seen in organized thrombi or fibrinous clots in hemorrhagic infarcts 5. Pulmonary Embolism ​ Occlusion of pulmonary artery or branches by thrombus ​ Ischemic coagulative necrosis in affected lung parenchyma ​ Possible hemorrhagic infarct (if dual blood supply is compromised)- a lot of tiny hemorrhages on top right corner ​ Alveolar septal thickening and congestion (2nd picture) ​ Infiltration of neutrophils in cases of infarction (2nd picture)...The dark, more intensely eosinophilic (pink) region in the upper right corner likely represents a hemorrhagic infarct of the lung 6. Pulmonary Edema ​ Alveolar spaces filled with pink-staining fluid (transudate- protein poor)..picture 1, more clear on picture 3 ​ Engorged capillaries in alveolar septa (picture 1) ​ Hemosiderin-laden macrophages ("heart failure cells") in chronic cases…picture 4 ​ Thickened alveolar walls due to interstitial edema ​ Possible hyaline membranes in severe cases (acute respiratory distress syndrome) 7. Coagulative Necrosis ​ Eosinophilic, anucleate hepatocytes ​ Preserved cell architecture with ghost-like cell outlines ​ Cytoplasmic condensation and increased eosinophilia ​ Karyolysis, pyknosis, or karyorrhexis of nuclei ​ Inflammatory cell infiltrate at the periphery (neutrophils initially, macrophages later) ​ Sinusoidal congestion and blood pooling (if ischemic origin) ​ Delayed removal of necrotic hepatocytes by macrophages