Iran Specialty Board Pathology key terms

Irreversible cell injury in living tissue marked by swelling, membrane rupture, and inflammation, with subtypes such as coagulative, liquefactive, caseous, and fat necrosis distinguished by tissue architecture and cause.

Programmed cell death executed by caspases, producing cell shrinkage, chromatin condensation, and apoptotic bodies without inflammation; central to development, tissue homeostasis, and elimination of damaged cells.

Reversible replacement of one mature epithelial or mesenchymal cell type by another better adapted to stress, such as squamous metaplasia of bronchial epithelium in smokers; often a precursor to dysplasia.

Disordered, atypical cellular growth with loss of uniformity and architectural orientation, graded as mild, moderate, or severe; severe dysplasia confined by the basement membrane overlaps with carcinoma in situ.

Malignant epithelial proliferation with full-thickness cytologic atypia that respects the basement membrane and has not invaded stroma; curable by local excision but a direct precursor of invasive carcinoma.

Rapid intraoperative tissue preparation by freezing and cutting, used for margin assessment, diagnosis of suspicious lesions, and confirmation of adequate material, with accuracy limited by artifact and sampling.

Systematic macroscopic description of a specimen including dimensions, color, consistency, tumor size, margins, and lymph node retrieval, dictating sampling and forming the basis of the final pathology report.

Structured, standardized checklist format for cancer pathology reports that records each required element such as grade, margins, lymphovascular invasion, and nodal status, improving completeness and comparability for treatment decisions.

Pathologic staging system combining extent of the primary tumor, regional lymph node metastases, and distant metastases after resection; the strongest prognostic factor and a determinant of adjuvant therapy.

First draining node identified by dye or radiotracer mapping; its histologic status predicts regional spread and guides axillary or other nodal dissection in breast cancer and melanoma.

Standardized reporting framework for cervical cytology that assigns a specimen adequacy statement and a diagnostic category such as NILM, ASC-US, LSIL, HSIL, or carcinoma, with defined management implications.

High-grade squamous intraepithelial lesion on cytology, reflecting full-thickness or near full-thickness dysplasia corresponding to CIN2-CIN3 histology; requires colposcopy and excision or ablation.

Molecular detection of high-risk human papillomavirus DNA or RNA used for primary cervical screening, triage of ASC-US, and post-treatment surveillance; negative results carry very high negative predictive value.

Minimally invasive sampling of a mass with a thin needle; material is smeared or liquid-based and assessed for cellularity and morphology, with cell blocks and ancillary immunocytochemistry extending diagnostic yield.

Immediate microscopic assessment of aspirate smears during a procedure to confirm adequacy, triage ancillary testing such as flow cytometry or cultures, and reduce repeat sampling; improves diagnostic yield.

Concentrated cytologic material processed as a paraffin-embedded pellet, permitting thin sections, immunohistochemistry, and molecular testing that parallel histologic specimens.

Wright-Giemsa stained blood film examined for red cell size, shape, and inclusions, white cell differential, and platelet number and morphology; the first-line morphologic test in hematologic disease.

Paired samples assessing cellularity, lineage maturation, infiltrates, and fibrosis; the aspirate suits morphology and flow cytometry while the trephine reveals architecture and is essential for lymphoma staging.

Laser-based technique quantifying surface and intracellular markers on single cells; used for leukemia and lymphoma immunophenotyping, minimal residual disease detection, and paroxysmal nocturnal hemoglobinuria testing.

Antibody-based detection of antigens in fixed tissue sections using chromogenic or fluorescent labels; guides tumor classification, determination of primary site, prognostic markers, and predictive biomarker testing.

Presence of a single immunoglobulin clone detectable as a serum or urine M-protein, associated with myeloma, Waldenström macroglobulinemia, AL amyloidosis, or monoclonal gammopathy of undetermined significance.

Separation of serum proteins by charge into albumin, alpha, beta, and gamma fractions; a narrow gamma band suggests a monoclonal protein and prompts immunofixation and free light chain quantification.

Monoclonal free immunoglobulin light chains in urine that precipitate on heating and redissolve near boiling; detected today by urine immunofixation and serum free light chain assays.

Range encompassing a defined central proportion, usually 95 percent, of values from a healthy reference population; interpretation depends on partitioning by age and sex and on analytical method.

Ratio of standard deviation to mean expressed as a percentage, quantifying analytical imprecision; compared against total allowable error to judge whether a method is fit for clinical use.

Quality metric expressing process performance in defects per million opportunities; in the laboratory it integrates bias, imprecision, and total allowable error to set internal quality control rules.

Proficiency testing in which an external body sends unknown samples for analysis and compares participant results with peer or reference values; required for accreditation and laboratory licensing.

Independent formal recognition that a laboratory meets a recognized standard such as ISO 15189 or CAP requirements, based on document review, on-site inspection, and ongoing proficiency testing performance.

Mistake occurring before analysis, including misidentification, improper collection tube, hemolysis, delayed transport, or inadequate fixation; the largest single source of laboratory errors.

Mass spectrometry method identifying bacteria and fungi by their protein spectral fingerprint within minutes from a colony, accelerating organism identification compared with biochemical panels.

Determination of the lowest antimicrobial concentration inhibiting visible growth, reported as minimum inhibitory concentration or category; guides therapy and detects resistance mechanisms such as extended-spectrum beta-lactamases.

Differential stain separating bacteria into gram-positive and gram-negative groups by cell wall structure, revealing morphology and arrangement; a rapid, inexpensive first step in specimen triage.

Enzymatic amplification of a targeted nucleic acid segment across thermal cycles; used for pathogen detection, clonality assessment, mutation analysis, and quantification with real-time fluorescent monitoring.

Massively parallel sequencing of many DNA fragments simultaneously, enabling panel, exome, or genome analysis for diagnostic variants, tumor mutation profiling, and copy number assessment.

Tumor suppressor protein that halts the cell cycle or triggers apoptosis after DNA damage; TP53 mutation is the most common genetic alteration in human cancer and is detectable by immunohistochemistry.

Digitization of an entire glass slide at diagnostic magnification into a pyramidal image file that can be viewed, shared, and analyzed remotely; the technical basis of digital pathology.

Documented comparison of diagnoses made on digital images against glass slides, covering all specimen types and users, required before clinical use and repeated after major system changes.

Remote interpretation of pathology images transmitted between sites, used for frozen section consultation, second opinions, and underserved-area coverage; depends on image quality and connectivity.

Postmortem examination combining external inspection, organ dissection, histology, and ancillary tests to establish cause of death, identify missed diagnoses, and support quality assurance and medico-legal inquiry.

Documented, unbroken record of who collected, handled, and stored a specimen or evidence from acquisition through analysis and court presentation, ensuring admissibility and integrity in forensic cases.

Proportion of diseased people correctly identified as positive and proportion of non-diseased correctly identified as negative; intrinsic test properties independent of disease prevalence in the tested population.

Probability that a person with a positive test truly has the disease; unlike sensitivity, it depends strongly on disease prevalence and falls when the condition is rare.

Ratio of the probability of a given test result in diseased versus non-diseased people; used with pretest odds to calculate post-test probability and to compare diagnostic tests.

Reciprocal of the absolute risk reduction, giving the number of patients who must receive an intervention for one additional favorable outcome; a clinically intuitive measure of treatment benefit.