Pathomorphology review for the midterm, first semester 2026

What kind of reversible and irreversible changes can be observed in the cells?

Reversible change

• steatosis

• glycogenic degeneration

• cellular swelling.

Irreversible change

• cytoplasmic change

• nuclear lesions

• cell membrane rupture.

Give the example of reversible and irreversible change

• Example of Reversible Change: Fatty liver (steatosis) or intranuclear glycogen accumulation in hepatocytes.

• Example of Irreversible Change: Coagulative necrosis of cardiac muscle cells (acute myocardial infarct) or enzymatic fat necrosis (acute pancreatitis).

The definition of hypertrophy and hyperplasia

Hyperplasia is an increase in the number of cells, while hypertrophy is an increase in the size of cells.

Give example of hypertrophy and hyperplasia

• Hypertrophy of skeletal muscles in bodybuilders or athletes due to an increased workload.

• Liver regeneration after a partial hepatectomy

What is atrophy?

Atrophy is a decrease in cell size and metabolic activity, which leads to the shrinkage of an organ or tissue. The cells are smaller and have reduced function, but they are not dead.

Give the example of atrophy

• Muscle wasting after losing nerve supply

• The shrinking of the uterus after giving birth.

What is metaplasia?

Metaplasia is a reversible change where one mature cell type is replaced by another mature cell type. It happens because of chronic stress or irritation, replacing weak cells with tougher ones that can survive the harsh environment.

Give the example of metaplasia

• In chronic smokers, delicate columnar lung cells change into tough squamous cells to survive cigarette smoke.

• In acid reflux (GERD), flat squamous cells in the esophagus change into columnar cells to resist stomach acid.

• Columnar cells change into squamous cells due to the acidic environment of the vagina.

What is the definition of necrosis in the living organism associated with inflammation?

necrosis is defined as cell death in living tissue resulting from acute stress to which a cell must react. It triggers an inflammatory response where immune cells infiltrate the dead tissue.

What is the nuclear change that can be observed in the cell during necrosis?

• Pyknosis – the nucleus becomes smaller and stains deeply

  basophilic

  Karyorrhexis – when pycnotic nucleus brake up into many

  smaller fragments scattered about the cytoplasm

  Karyolysis – when pycnotic nucleus is extruded from the

  cell

1. What are the type of necrosis?

• Coagulative necrosis: Characterized by denaturation of cytoplasmic proteins, breakdown of cell organelles, and cell swelling (e.g., acute myocardial infarct).

• Enzymatic fat necrosis: Involves focal areas of fat destruction occurring in acute pancreatitis due to the release of activated pancreatic lipases.

• Traumatic fat necrosis: Occurs in adipose tissue as a result of injury, commonly seen in the female breast.

• Caseous necrosis: Briefly mentioned as an area where dystrophic calcification can be encountered.

• Liquefactive necrosis: Briefly mentioned as an area where dystrophic calcification can be encountered.

• Hemorrhagic infarct (ischemic necrosis): Mentioned in the context of tissue death caused by vascular occlusion, such as in the lung.

The most common organ where you can find a particular type of necrosis? e.g., List 2 organs that you can find karyolysis in.

1. The Heart (Cardiac Muscle): Seen during coagulative necrosis in an acute myocardial infarct, where cardiomyocytes lose their nuclei.

2. The Lung: Seen during hemorrhagic infarction of the lung, where the necrotic alveolar and vascular walls lack nuclei.

What is the composition of a caseous cell granuloma?

1. Central Core: Caseous Necrosis

• Composition: Formed by the necrotic debris of dead cells (mostly macrophages and structural tissue).

• Microscopic Appearance: Appears as a structureless, homogeneous, granular, and strongly eosinophilic (pink) material that lacks cellular nuclei. Much of the Mycobacterium tuberculosis bacteria is concentrated here.

2. Intermediate Layer: Epithelioid Cells & Giant Cells

• Epithelioid Cells (Activated Macrophages): Specialized macrophages that undergo a morphological transformation. Under the microscope, they display abundant pink cytoplasm and elongated, vesicular nuclei, packing tightly together like epithelial sheets (hence "epithelioid").

• Langhans Multinucleated Giant Cells: Distinctive massive cells formed by the fusion of several activated macrophages. They are characterized by a horseshoe-shaped or peripheral ring arrangement of nuclei along the outer border of the cell's cytoplasm.

3. Peripheral Rim: Chronic Inflammatory Cells

• Lymphocytes: A dense outer mantle consisting primarily of T-lymphocytes (CD4+ and CD8+) and B-lymphocytes that orchestrate the delayed-type hypersensitivity immune response against the mycobacteria.

• Plasma Cells: Interspersed among the lymphocytes, producing localized antibodies.

4. Outer Wall: Fibroblastic Margin

• Fibroblasts & Collagen: In well-established or chronic lesions, an outer layer of fibroblasts deposits a dense connective tissue wall (fibrosis) to encapsulate the infection site and isolate it from the rest of the lung or lymph node tissue.

List 2 features to differentiate apoptosis and necrosis?

1. Inflammatory Response:

   • Necrosis: Always triggers an inflammatory response where immune cells infiltrate the dead tissue.

   • Apoptosis: Does not trigger an inflammatory response.

2. Cell Membrane Integrity:

   • Necrosis: Involves cell membrane rupture and fragmentation, causing the cell contents to spill out.

   • Apoptosis: The cell membrane remains intact, breaking down into membrane-bound apoptotic bodies without spilling cellular contents.

What is the definition of degeneration, and give the type and example?

Definition:

Degeneration is a reversible cell injury where cells get damaged due to metabolic problems, leading to an abnormal buildup of substances inside them. If the stress stops, the cells can go back to normal.

Types and Examples:

• 1. Lipid Degeneration (Steatosis): Abnormal buildup of fat inside cells.

  • Example: Fatty liver, where big fat droplets fill up liver cells.

• 2. Glycogen Degeneration: Abnormal buildup of glycogen (sugar).

  • Example: Intranuclear glycogen accumulation, where liver cell nuclei look "empty" or ballooned because they are filled with glycogen.

• 3. Mineral Degeneration (Calcification): Abnormal buildup of calcium salts.

  • Example: Pathologic calcification in the kidney, which leaves dark, purple-stained mineral deposits in the tissue.

What is the definition of "steatosis"?

• The general definition: It is the accumulation of fat in non-fatty cells (lipid degeneration).

What is liver steatosis (the fatty liver), and what is the cause?

it’s a abnormal accumulation of triglycerides within hepatocytes, and the cause can be from Alcoholic Liver Disease (ALD),Non-Alcoholic Fatty Liver Disease (NAFLD),Metabolic Dysfunction-Associated Steatotic Live Disease (MASLD), Drugs, wilson’s disease, weight loss, malnutrition, HCV

What is the type of liver steatosis ?

Macrovesicular Steatosis and Microvesicular Steatosis

The extra straining to visualise fat in the tissue for fatty liver

sudan or Oil red

Cause of fat degeneration?

• Obesity

• Congenital hyperlipidemia

• Chronic illnesses (e.g., tuberculosis)

• Acute fatty liver in late pregnancy

• Hypoxia (e.g., anemia, cardiac failure)

• Hepatotoxins (e.g., carbon tetrachloride, chloroform, ether, aflatoxins, and other poisons)

• Drug-induced liver cell injury (e.g., administration of methotrexate, steroids, $CCl_4$, halothane anesthetic, tetracycline, etc.)

• Reye’s syndrome

Cause of glycogenic degeneration?

cause are diabetes, circulatory failure, hyperthyroidism, acute childhood diseases

The extra straining to visualise the glycogen in the hepatocyte or inside the cell

Periodic acid–Schiff (PAS) stain (most common)

best carmin

The calcification of the kidney are what type of degeneration?

Calcification of the kidney is an example of mineral degeneration.

the type of calcification are:

Dystrophic and Metastatic

dystrophic and metastatic and what is the different between 2 of them ไม่ชัวร์กับคำตอบ

Dystrophic Calcification

• occur in areas of necrosis, relate to serum level of calcium ions is normal or lower, caused by Tissue Necrosis, Specific Types of Necrosis Vascular Damage

Metastatic Calcification

• Metastatic calcification may occur in normal tissues whenever there is hypercalcemia. Caused by hyperparathyroidism, vitamin D-related disorder, bone resorption tumor of bone marrow, or renal failure

What are the 4 major causes of hypercalcemia?

1. Hyperparathyroidism

2. Vitamin D-related disorders (Vitamin D intoxication)

3. Bone resorption (due to tumors of bone marrow, such as multiple myeloma, or diffuse skeletal metastases)

4. Renal failure (which leads to secondary hyperparathyroidism)

List at least 2 Dystrophic calcification , where can we find it?

• Areas of tissue necrosis

• Advanced atheromas(ก้อนไขมัน) of blood vessels

• aging or damaged heart valve

what is Pigment degeneration ?

Pigment degeneration is the abnormal intracellular or extracellular accumulation of pigments, which can be endogenous or exogenous , leading to cellular injury or dysfunction.

Example of endogenous and exogenous pigment and type?

endogenous (originating within the body, like melanin, lipofuscin, or hemosiderin)

exogenous (coming from the outside, like carbon or tattoos)

What are the 2 most common causes of myocardial infarction? 

• sudden disruption of an atheromatous plaque การแตกตัวอย่างฉับพลันของคราบไขมันในหลอดเลือด

• thrombosis ลิ่มเลือดอุดตัน

The 4 stages of myocardial infarction?

1.acute myocardial infarct (recent myocardial infarct)

2.myomalacia of the m. infarct (fagocytosis of the m. infarct)

3.organization of the m. infarct (healing myocardial infarct)

4.scarred myocardial infarct (healed myocardial infarct, remote m. infarct, old m. i.)

What is the extra straining of scar tissue in the heart?

VAN GIESON method in which:

CONNECTIVE TISSUE is PINK

Cytoplasm of the cells, muscle,

RBC are YELLOWISH.

Nuclei are BROWN to BLACK.method,

What is the cause of enzymatic fat necrosis (acute pancreatitis)?

The release of activated pancreatic enzymes (lipase) due to acute pancreatitis or abdominal trauma.

What are the definition and type of edema?

Edema is the abnormal accumulation of excess fluid in the interstitial tissue spaces or body cavities.

Type : Cardiogenic Edema and Non-Cardiogenic Edema

What is the most common cause of cardiogenic edema?

The most common cause of cardiogenic edema is Congestive Heart Failure (CHF) and the Left-sided heart failure is more common than Right-sided heart failure

• Left-sided heart failure is the most common cause of cardiogenic pulmonary edema (fluid in the lungs).

• Right-sided heart failure is the most common cause of cardiogenic peripheral edema (fluid in the legs and dependent tissues).

2 examples of cause of non-cardiogenic edema

Negative pressure pulmonary edema

Neurogenic causes (seizures, head trauma, strangulation, electrocution).

Pulmonary embolism

Acute lung injury

The two most frequently taught and classic examples from your list are the following:

• Acute lung injury

• sepsis

What is the cause of pulmonary edema

due to either failure of the left ventricle of the heart to remove blood

adequately from the pulmonary circulation (cardiogenic pulmonary

edema), or an injury to the lung tissue or blood vessels of the lung

(non-cardiogenic pulmonary edema)

What is the definitions of hyperemia and congestion?

Hyperemia is an active process resulting from increased tissue influx of blood because of arteriolar dilation. The affected tissue turns red (erythema) because there is a lot of oxygenated blood.

Congestion is a passive process resulting from decreased outflow of venous blood from a tissue. The affected tissue turns a blue-red color (cyanosis) because there is a lot of deoxygenated blood.

What is the most common cause of chronic congestion of the liver?

Right-sided heart failure.

what are cause of Chronic congestion of the liver

The causes of chronic congestion of the liver include:

• Right-sided heart failure (the most common cause)

• Hepatic vein obstruction (Budd-Chiari syndrome)

• Inferior vena cava (IVC) obstruction

What are the stages of chronic congestion of the liver?

1. Acute Passive Congestion: The initial backup of blood into the central veins.

2. Chronic Congestion (Nutmeg Liver): Long-term congestion creating the characteristic red-and-yellow speckled appearance.

3. Centrilobular Atrophy: The dying off and shrinking of liver cells in the center of the lobules due to a lack of oxygen.

4. Fibrosis (Cardiac Sclerosis): The final stage where scar tissue forms around the damaged central areas, also known as cardiac cirrhosis.

What is the definition of thrombus?

the formation of a blood clot within blood vessels, limiting the natural flow of blood and resulting in clinical complication.

What are the types of thrombus?

2 main type are

1.Arterial thrombi (characterized by predominance of platelets)

2.Venous thrombi(characterized by predominance of red blood cells )