CVS

Gross Image Clue: A cardiac ventricular slice from a patient who died $3\,\text{days}$ after severe substernal chest pain shows a central pale yellow-tan soft region with a hyperemic red border. What is the diagnosis and key gross features according to Ramdas Nayak?

Diagnosis: Acute Myocardial Infarction ($2\text{-}4\,\text{days}$ old)

Key Gross Features (Ramdas Nayak):

• Color/Appearance: Central yellow-tan softening with a surrounding hyperemic (red) rim of vascular congestion and early inflammation

• Location: Most commonly subendocardial or transmural in the distribution of LAD, RCA, or LCX

• Diagnostic Hallmark: Yellow-tan center surrounded by a hyperemic hypervascular border

Microscopic Image Clue: Left ventricular myocardium shows loss of cardiac muscle striations and nuclei, hypereosinophilic myofibers, and dense interstitial infiltration by neutrophils. What is the diagnosis and characteristic microscopic features?

Diagnosis: Acute Myocardial Infarction ($12\text{-}72\,\text{hours}$)

Microscopic Features (Ramdas Nayak):

• Low-Power: Band of necrotic myocardium with dense acute inflammatory cell infiltration at the periphery

• High-Power: Coagulative necrosis of myocytes (loss of nuclei and striations, intense hypereosinophilia)

• Infiltrate: Dense neutrophilic infiltrate between necrotic myocytes

• Diagnostic Hallmark: Coagulative necrosis of cardiac myocytes with dense neutrophilic infiltrate

Microscopic Image Clue: Myocardial section demonstrates a focal granulomatous lesion containing central fibrinoid necrosis surrounded by lymphocytes, plasma cells, and large macrophages with vesicular nuclei and ribbon-like chromatin. What is the lesion and its pathognomonic cells?

Diagnosis: Aschoff Body in Rheumatic Carditis

Microscopic Features (Ramdas Nayak):

• Central Region: Fibrinoid necrosis of collagen

• Cellular Infiltrate: T lymphocytes, plasma cells, and pathognomonic histiocytes

• Key Pathognomonic Cells:

  • Anitschkow cells: Large histiocytes with abundant cytoplasm and central caterpillar-like chromatin on longitudinal section ("owl-eye" on cross section)

  • Aschoff giant cells: Multinucleated giant cells derived from macrophages

• Diagnostic Hallmark: Aschoff body containing pathognomonic Anitschkow ("caterpillar") cells

Gross Image Clue: Mitral valve viewed from the left atrium shows severe thickening and fusion of leaflet commissures, thickened and shortened chordae tendineae, and a rigid, narrowed orifice. What is the diagnosis and characteristic gross morphology?

Diagnosis: Chronic Rheumatic Heart Disease (Mitral Stenosis)

Key Gross Features (Ramdas Nayak):

• Valve Leaflets: Diffuse fibrous thickening, calcification, and commissural fusion
• Chordae Tendineae: Thickened, shortened, and fused into a single fibrous column
• Orifice: Narrowed, rigid opening resembling a "fish-mouth" or "button-hole"
• Atrial Changes: Left atrial massive dilatation with MacCallum plaques on the posterior atrial wall
• Diagnostic Hallmark: Commissural fusion with "fish-mouth" or "button-hole" valvular deformity

Morphological Comparison: How do the vegetations of Rheumatic Heart Disease, Infective Endocarditis, Non-Bacterial Thrombotic Endocarditis (NBTE), and Libman-Sacks Endocarditis differ in size, friability, location, and bacterial presence?

1. Rheumatic Heart Disease (RHD):

• Small ($1\text{-}2\,\text{mm}$), firm, warty (verrucous), sterile, along lines of closure (atrial surface of AV valves, ventricular surface of semilunar valves)

2. Infective Endocarditis (IE):

• Large ($>5\,\text{mm}$), bulky, friable, destructive, non-sterile (contains dense bacterial colonies), can extend onto chordae or valve ring

3. Non-Bacterial Thrombotic Endocarditis (NBTE):

• Small-to-medium ($1\text{-}5\,\text{mm}$), sterile, bland, non-destructive, loosely attached along closure lines in hypercoagulable states

4. Libman-Sacks Endocarditis (SLE):

• Small-to-medium, sterile, granular, located on both surfaces (underside and upper side) of valve leaflets, commissures, and endocardium

Microscopic Image Clue: Heart valve section shows a large, friable mass composed of dense fibrin, platelets, necrotic debris, neutrophilic infiltrate, and large bacterial colonies. What is the diagnosis and key histological components?

Diagnosis: Acute Infective Endocarditis

Microscopic Features (Ramdas Nayak):

• Superficial Zone: Dense layer of fibrin, platelets, and bacterial colonies (microorganisms)
• Base Zone: Intense neutrophilic acute inflammatory reaction and underlying granulation tissue
• Deep Zone: Suppurative necrosis destroying underlying valvular collagen
• Diagnostic Hallmark: Friable vegetation containing dense bacterial colonies mixed with fibrin and neutrophils on destroyed valvular tissue

Gross Image Clue: Abdominal aorta opened posteriorly shows raised, yellow-white focal intimal lesions with ulceration, calcification, and overlying mural thrombi. What is the lesion and its gross structural components?

Diagnosis: Advanced Atherosclerotic Plaque (Atheroma)

Key Gross Features (Ramdas Nayak):

• Surface: Raised yellow to white-grey eccentric intimal plaques

• Complications: Ulceration, calcification (brittle, eggshell-like), intra-plaque hemorrhage, and thrombosis

• Predilection Site: Abdominal aorta > Coronary arteries > Popliteal arteries > Internal carotid arteries

• Diagnostic Hallmark: Raised eccentric yellow intimal plaque with central lipid core and fibrous cap

Microscopic Image Clue: Arterial wall section demonstrates a prominent fibrocellular cap covering a necrotic core containing cholesterol clefts, lipid-laden foam cells, necrotic debris, and focal calcification. What is the diagnosis and key histological features?

Diagnosis: Atherosclerotic Plaque

Microscopic Features (Ramdas Nayak):

• Fibrous Cap: Smooth muscle cells, dense collagen, elastic fibers, and scattered lymphocytes
• Necrotic Core: Acellular core containing needle-like cholesterol clefts (empty spaces left after tissue processing), necrotic cell debris, and calcium deposits
• Basal/Peripheral Region: Foam cells (lipid-laden macrophages) and neovascularization (capillaries)
• Diagnostic Hallmark: Needle-shaped cholesterol clefts within a central necrotic core beneath a fibrous cap

Gross Image Clue: Opened pericardial sac demonstrates a dry, roughened, opaque pericardial surface with shaggy, irregular exudate giving a "bread and butter" appearance. What is the diagnosis and key gross features?

Diagnosis: Fibrinous / Serofibrinous Pericarditis

Key Gross Features (Ramdas Nayak):

• Pericardial Surface: Thickened, dull, opaque, and shaggy with dense fibrinous exudate
• Appearance: "Bread and butter" appearance (resembles two buttered slices of bread pulled apart)
• Fluid: Variable serous fluid mixed with fibrin strands
• Etiology Clue: Uremia, acute myocardial infarction (Dressler syndrome/early post-MI), rheumatic fever, or viral infection
• Diagnostic Hallmark: Shaggy, fibrous "bread and butter" surface exudate

Image Clue: Radial artery section from an elderly patient shows ring-like calcifications restricted to the tunica media without narrowing of the arterial lumen or intimal disruption. What is the diagnosis and distinguishing morphological features?

Diagnosis: Mönckeberg Medial Calcific Sclerosis

Morphological Features (Ramdas Nayak):

• Gross: Hard, rigid, pipe-stem-like non-compressible arteries ("pipestem arteries"); intact lumen
• Microscopy (Tunica Media): Basophilic ring-like calcification along the internal elastic lamina and media
• Microscopy (Tunica Intima): Normal intimal layer without occlusion or lipid accumulation
• Clinical/Diagnostic Hallmark: Ring-like medial calcification that does not narrow the vessel lumen