Arab Board Anatomic Pathology Part 1 key terms

Programmed cell death in which a cell shrinks, condenses its chromatin, and breaks into membrane-bound bodies that are quietly removed by neighboring cells or macrophages, without inflammation. It is energy-dependent and tightly regulated by genes and caspases.

A pattern of cell death, typical of ischemic injury in solid organs except the brain, in which tissue architecture is preserved for days as a firm, eosinophilic ghost outline while nuclei disappear and inflammatory cells later move in.

A reversible change in which one mature, differentiated cell type is replaced by another mature type that better tolerates stress, such as squamous cells replacing columnar respiratory epithelium in chronic smokers. The change is adaptive but may predispose to dysplasia.

A compact, organized collection of activated macrophages (epithelioid cells), often with multinucleated giant cells and a rim of lymphocytes, formed to contain organisms or foreign material that are hard to eliminate. Caseous necrosis suggests tuberculosis.

The three factors that promote thrombosis: endothelial injury, abnormal blood flow such as stasis or turbulence, and hypercoagulability of the blood. Each factor can act alone or in combination, and clinical risk assessment considers all three.

Disordered, non-physiological proliferation in which cells show variation in size and shape, nuclear enlargement and hyperchromasia, and disturbed maturation, but the change has not crossed the basement membrane. Severe dysplasia is a precursor of invasive carcinoma.

Additional cell damage that occurs when blood flow is restored to ischemic tissue, driven by a burst of reactive oxygen species, calcium overload, complement activation, and neutrophil influx, which can worsen injury beyond that caused by ischemia alone.

A chronic disease of large and medium arteries in which lipid-rich, inflammatory plaques form within the intima, with foam cells, fibrosis, and a necrotic core that can calcify. Plaque rupture or erosion triggers thrombosis and ischemic events.

An end-stage liver reaction in which diffuse fibrosis and regenerative nodules replace normal architecture, causing portal hypertension and impaired synthetic and metabolic function. Common causes include chronic hepatitis, alcohol, and metabolic disease.

A rapidly progressive glomerular disease in which proliferating cells and macrophages fill Bowman space to form crescents, damaging the capillary tuft and producing hematuria, proteinuria, and renal failure over weeks. It often reflects severe immune-mediated capillary injury.

Necrosis of heart muscle extending across the full thickness of the ventricular wall from endocardium to epicardium, usually from complete coronary artery occlusion. It carries higher risks of rupture, aneurysm, and pericarditis than partial-thickness infarction.

Lung infection that spreads through small airways to produce patchy, bilateral areas of neutrophilic consolidation centered on bronchi and bronchioles, rather than a single confluent lobe. It is common in the elderly, debilitated, and hospitalized patients.

The standard method of preserving tissue by cross-linking proteins with buffered formaldehyde solution, which hardens tissue, prevents autolysis and decay, and allows thin sections to be cut. Adequate time and concentration are needed for consistent staining.

A rapid intraoperative technique in which fresh tissue is frozen, cut in a cryostat, and stained within minutes to answer a specific question, such as margin status or the nature of a mass. Morphology is inferior to permanent sections and some tissues freeze poorly.

The routine histology stain in which hematoxylin, a basic dye, colors nuclei blue-purple, while eosin, an acidic dye, colors cytoplasm and extracellular proteins pink. The contrast reveals tissue architecture and is the foundation for most diagnostic microscopy.

The process of removing calcium salts from bone or calcified tissue with acid or chelating agents so that it can be cut without tearing. Over-decalcification can damage nucleic acids, antigens, and morphology, so endpoint monitoring matters.

A distortion caused by heat from surgical electrocautery, producing stretched, spindled, hyperchromatic cells that can mimic malignancy at the edges of a specimen. Recognizing the clinical context and the linear pattern prevents a false-positive diagnosis.

A standardized reporting framework for cervical cytology that defines specimen adequacy, general categorization, and specific interpretations such as atypical squamous cells, low-grade or high-grade lesions, with management-linked terminology that clinicians can act on consistently.

A cytology preparation method in which the sample is rinsed into a preservative fluid, then processed to produce a thin, uniform layer of cells. It reduces obscuring blood and inflammation and allows ancillary HPV testing from the same vial.

A minimally invasive sampling technique using a thin needle and suction to obtain cells and small tissue fragments from a palpable or image-guided mass for cytologic examination, useful in thyroid, breast, lymph node, and salivary gland lesions.

A cytology preparation in which centrifuged or sedimented cellular material is embedded in paraffin so that it can be sectioned like a surgical biopsy, permitting multiple stains, immunohistochemistry, and molecular testing on cytology samples.

A Bethesda System interpretation meaning atypical squamous cells of undetermined significance, a minor cytologic abnormality that may reflect transient infection, reactive change, or a small high-grade lesion, typically triaged with HPV testing or repeat cytology.

A pretreatment step in immunohistochemistry, using heat or enzymes, that unmasks epitopes hidden by formalin cross-linking so antibodies can bind. The method must be validated for each antibody because inappropriate retrieval weakens or creates false staining.

Laboratory assessment of HER2 protein by immunohistochemistry, or of gene amplification by in situ hybridization, in breast and gastric cancers to determine eligibility for anti-HER2 therapy. Scoring follows defined criteria with internal and external controls.

Fluorescence in situ hybridization: a technique in which fluorescently labeled probes bind specific DNA sequences on a slide, revealing gene amplification, deletion, or rearrangement as colored signals in interphase nuclei or metaphase chromosomes.

A molecular phenotype in which short repetitive DNA sequences change length due to defective mismatch repair, detected by PCR or next-generation sequencing. It occurs in Lynch syndrome and some sporadic tumors and predicts response to immune checkpoint inhibitors.

A massively parallel DNA sequencing approach that reads millions of fragments simultaneously, allowing detection of mutations, copy-number changes, and fusions in many genes from limited tissue, with bioinformatics filtering and variant interpretation required.

An inherited hemoglobin disorder in which abnormal hemoglobin S polymerizes when deoxygenated, deforming red cells into rigid crescents that cause vaso-occlusion, hemolysis, and painful crises. Diagnosis uses peripheral blood smear and hemoglobin electrophoresis.

A group of clonal bone marrow disorders with ineffective blood cell production, showing dysplastic features and cytopenias that may progress to acute myeloid leukemia. Diagnosis requires marrow examination with karyotype and blast quantitation.

A severe reaction, usually caused by ABO-incompatible red cells, in which antibodies destroy donor erythrocytes within minutes to hours, producing fever, chills, back pain, hemoglobinuria, and possibly shock or renal failure. Stop the transfusion immediately.

A technique in which single cells labeled with fluorescent antibodies pass through a laser beam, allowing rapid measurement of surface markers and cell size to characterize leukemias, lymphomas, and immunodeficiencies.

Postmortem settling of blood in dependent vessels due to gravity, producing purplish discoloration of the skin that begins within an hour and becomes fixed after several hours. The pattern can suggest body position after death.

Postmortem stiffening of muscles caused by depletion of ATP, which prevents myosin heads from detaching from actin. It begins in small muscles of the face and neck and then spreads, resolving later as decomposition proceeds.

A classification of how a death came about, natural, accident, suicide, homicide, or undetermined, distinct from the cause, which is the disease or injury producing death. It is assigned by a medical examiner or coroner.

The proportion of people who truly have a condition and are correctly identified by a test. It reflects the test's ability to detect disease, and highly sensitive tests are useful for screening because false negatives are few.

The proportion of people with a positive test result who actually have the condition. It depends on disease prevalence as well as test sensitivity and specificity, so values fall when the condition is rare.

A measure of assay precision calculated as the standard deviation divided by the mean, expressed as a percentage. It allows comparison of variability between tests with different scales and is monitored in quality control.

A quality control graph plotting successive control results against time with lines for the mean and standard deviation limits, making trends, shifts, and random error visible so that runs can be accepted or rejected under defined rules.