Histology Medical Stuff

Anaplasia

Loss of cellular differentiation; malignant cells show marked atypia and little resemblance to their tissue of origin.

Pleomorphism

Variation in the size and shape of tumor cells and their nuclei.

Hyperchromasia

Abnormally dark-staining nuclei caused by increased DNA content and condensed chromatin.

Increased nuclear-to-cytoplasmic ratio

A feature of malignant cells in which the nucleus is disproportionately large compared with the cytoplasm.

Atypical mitoses

Abnormal mitotic figures with irregular chromosome distribution, commonly seen in malignant tumors.

Tumor giant cells

Abnormally large tumor cells, often containing multiple or unusually large nuclei.

Carcinoma

A malignant neoplasm arising from epithelial cells.

Sarcoma

A malignant neoplasm arising from mesenchymal or connective tissue cells.

Adenocarcinoma

A malignant epithelial tumor showing glandular differentiation.

Squamous cell carcinoma

A malignant epithelial tumor arising from squamous cells.

Benign tumor

A neoplasm that remains localized and does not invade or metastasize.

Malignant tumor

A neoplasm that can invade surrounding tissues and may metastasize.

Metastasis

The spread of malignant tumor cells from the primary site to a distant location.

Differentiation

The degree to which tumor cells resemble the normal cells of their tissue of origin.

Dysplasia

Disordered epithelial growth and maturation with cellular and nuclear atypia; it is not invasive cancer.

Carcinoma in situ

Severe epithelial dysplasia involving the full epithelial thickness without invasion through the basement membrane.

Desmoplasia

Formation of dense fibrous connective tissue in response to an invasive tumor.

Lipoma

A benign mesenchymal tumor composed of mature adipocytes.

Liposarcoma

A malignant mesenchymal tumor showing adipocytic differentiation.

Leiomyoma

A benign tumor of smooth muscle; uterine leiomyomas are also called uterine fibroids.

Leiomyosarcoma

A malignant tumor arising from smooth muscle cells.

Osteosarcoma

A malignant bone-forming tumor in which tumor cells produce osteoid.

Melanoma

A malignant tumor arising from melanocytes.

Lymphoma

A malignant neoplasm arising from lymphocytes or other lymphoid cells.

MALT lymphoma

A B-cell lymphoma arising from mucosa-associated lymphoid tissue.

Mesothelioma

A malignant tumor arising from mesothelial cells lining serous cavities, especially the pleura; strongly associated with asbestos exposure.

Hepatocellular carcinoma (HCC)

A malignant tumor arising from hepatocytes.

Gastric adenocarcinoma

A malignant gland-forming epithelial tumor arising from the stomach lining.

Colorectal adenocarcinoma

A malignant gland-forming epithelial tumor arising from the colorectal mucosa.

Pancreatic ductal adenocarcinoma

A malignant epithelial tumor arising from the ductal cells of the pancreas.

Retinoblastoma

An inherited cancer predisposition syndrome caused by mutation of the RB1 tumor suppressor gene; associated with childhood retinal tumors.

Li-Fraumeni syndrome

An inherited cancer predisposition syndrome caused by mutation of TP53, increasing the risk of multiple cancers at young ages.

Lynch syndrome

An inherited cancer predisposition syndrome caused by defective DNA mismatch repair; increases the risk of colorectal and other cancers.

Xeroderma pigmentosum

An inherited DNA repair disorder involving defective nucleotide excision repair, causing extreme sensitivity to UV radiation and increased skin cancer risk.

Familial adenomatous polyposis (FAP)

An inherited syndrome, usually caused by an APC gene mutation, characterized by numerous colorectal adenomatous polyps and a very high risk of colorectal cancer.

Barrett esophagus

Replacement of the normal stratified squamous epithelium of the lower esophagus by intestinal-type columnar epithelium, usually due to chronic acid reflux.

Squamous metaplasia

Replacement of one mature epithelial cell type by stratified squamous epithelium, often in response to chronic irritation.

Metaplasia

An adaptive change in which one differentiated cell type is replaced by another; persistent stress may increase the risk of dysplasia.

Cervical intraepithelial neoplasia (CIN)

A spectrum of precancerous cervical epithelial changes graded according to the thickness of the epithelium involved.

CIN 1

Mild cervical dysplasia involving approximately the lower one-third of the epithelium; classified as LSIL.

CIN 2

Moderate cervical dysplasia involving approximately the lower two-thirds of the epithelium; classified as HSIL.

CIN 3

Severe cervical dysplasia involving nearly the full thickness of the epithelium; classified as HSIL and equivalent to carcinoma in situ when there is no invasion.

Koilocyte

An HPV-infected squamous epithelial cell with a characteristic perinuclear halo and irregular, enlarged nucleus.

Human papillomavirus (HPV)

A virus associated with cervical and other anogenital cancers; high-risk types can promote malignant transformation.

Helicobacter pylori

A bacterium associated with chronic gastritis, peptic ulcer disease, gastric adenocarcinoma, and MALT lymphoma.

Epstein-Barr virus (EBV)

A virus associated with Burkitt lymphoma, some cases of Hodgkin lymphoma, and nasopharyngeal carcinoma.

Hepatitis B and C viruses

Viruses associated with chronic liver inflammation and an increased risk of hepatocellular carcinoma.

Schistosoma haematobium

A parasitic infection associated with chronic bladder inflammation and an increased risk of urinary bladder squamous cell carcinoma.

Duchenne muscular dystrophy

An X-linked disorder caused by dystrophin deficiency (a protein that links the cytoskeleton and ECM to stabilize the sarcolemma during muscle contraction), leading to muscle fiber membrane damage, muscle degeneration, and progressive weakness.

Myasthenia gravis

An autoimmune disorder in which antibodies commonly target acetylcholine receptors at the neuromuscular junction, causing fatigable muscle weakness.

Botulism

A condition caused by botulinum toxin, which prevents acetylcholine release from presynaptic nerve terminals and produces flaccid paralysis.

Osteogenesis imperfecta

An inherited connective tissue disorder commonly caused by defects in type I collagen, resulting in fragile bones.

Tendinitis

Inflammation or irritation of a tendon, often associated with repetitive stress or injury.

Kwashiorkor

Severe protein deficiency despite relatively adequate calorie intake; classically causes edema, fatty liver, and impaired growth.

Marasmus

Severe deficiency of total calories and protein, causing marked loss of body fat and muscle mass.

Cystic fibrosis

An inherited disorder caused by CFTR dysfunction, resulting in abnormal ion and water transport and thick, sticky secretions.

Alpha-1 antitrypsin deficiency

An inherited disorder that can cause misfolded protein accumulation in hepatocytes and reduced protection of lung tissue from protease damage.

Hypertrophy

An increase in the size of individual cells, resulting in enlargement of a tissue or organ.

Hyperplasia

An increase in the number of cells within a tissue or organ.

Atrophy

A decrease in the size of a tissue or organ due to reduced cell size, cell number, or both.

Disuse atrophy

Reduction in muscle size caused by decreased workload or lack of use.

Denervation atrophy

Muscle wasting caused by loss of nerve stimulation.

Autophagy

A cellular process in which damaged or unnecessary cell components are enclosed in autophagosomes and degraded after fusion with lysosomes.

Fatty change

Abnormal accumulation of triglyceride droplets within cells, especially in organs involved in lipid metabolism.

Hepatic steatosis

Fatty change specifically involving accumulation of triglycerides within hepatocytes.

Reversible cell injury

Cell damage that can return to normal when the harmful stimulus is removed before irreversible injury occurs.

Cell swelling (hydropic change)

An early feature of reversible cell injury caused by impaired ion regulation and intracellular water accumulation.

Irreversible cell injury

Severe cell damage from which recovery is no longer possible, ultimately leading to cell death.

Necrosis

Uncontrolled cell death associated with loss of membrane integrity and inflammation in surrounding tissue.

Apoptosis

Programmed cell death involving controlled cell fragmentation and removal, usually without significant inflammation.

Apoptotic bodies

Membrane-bound fragments of a cell undergoing apoptosis that are removed by phagocytosis.

Coagulative necrosis

A pattern of necrosis in which tissue architecture is temporarily preserved because structural proteins and enzymes are denatured; commonly follows ischemia in solid organs.

Liquefactive necrosis

A pattern of necrosis in which enzymatic digestion turns tissue into a liquid or viscous mass; commonly seen in brain infarcts and abscesses.

Caseous necrosis

A pattern of necrosis characterized by soft, cheese-like material, classically associated with tuberculosis.

Fat necrosis

Destruction of adipose tissue, often involving release of fatty acids and formation of calcium soaps.

Fibrinoid necrosis

A pattern of tissue damage involving deposition of fibrin-like material in vessel walls, commonly associated with immune-mediated vascular injury.

Gangrenous necrosis

A clinical term for extensive tissue necrosis, usually involving an extremity; dry gangrene is predominantly coagulative necrosis, while wet gangrene includes infection and liquefaction.

Myocardial infarction

Death of heart muscle cells caused by prolonged ischemia, usually due to obstruction of a coronary artery.

Atherosclerosis

A chronic disease of large and medium-sized arteries characterized by lipid-rich plaques in the arterial wall.

Cerebral atrophy

Reduction in brain tissue volume due to loss or shrinkage of neurons and other brain cells.

Parkinson disease

A neurodegenerative disorder associated with loss of dopamine-producing neurons in the substantia nigra, causing impaired movement.

Huntington disease

An inherited neurodegenerative disorder associated with loss of neurons, particularly those using GABA in the brain, causing movement abnormalities and cognitive decline.

Alzheimer disease

A neurodegenerative disorder characterized by progressive neuronal and synaptic loss, amyloid plaques, and neurofibrillary tangles.

Multiple sclerosis

An autoimmune disease in which myelin in the central nervous system is damaged, disrupting nerve signal transmission.

Meningitis

Inflammation of the meninges, the coverings of the brain and spinal cord.

Oligodendroglioma

A tumor arising from oligodendrocytes or cells resembling oligodendrocytes in the central nervous system.

Malignant astrocytoma

A malignant tumor arising from astrocytes or astrocytic lineage cells in the central nervous system.