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Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

232 results found
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Histological stains

Histological stains are chemicals dyes used to treat histological specimens to make tissues more readily visible by light microscopy and demonstrate underlying characteristics of the tissue. There are many stains, some with very specific uses, whereas other (e.g. hematoxylin and eosin stain (H&E...
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Histology of blood vessels

Blood vessels, namely arteries and veins, are composed of endothelial cells, smooth muscle cells and extracellular matrix (including collagen and elastin). These are arranged into three concentric layers (or tunicae): intima, media and adventitia. the intima (or tunica intima) inner layer abut...
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Homer Wright rosettes

Homer Wright rosettes are differentiated tumor cells grouped around a central region containing neuropil (therefore its association with tumors of neuronal origin). Pathology Examples of tumors where these can be seen include: medulloblastoma (the presence of Homer Wright rosettes in a poster...
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Host (infectious diseases)

A host in the context of infectious disease refers to an animal or plant that acts as a biological refuge in which another - often parasitic - organism may dwell. The host usually provides shelter or nourishment to the other organism, which may use the host to partially/completely sexually devel...
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Human coronavirus

The human coronaviruses (hCoVs), members of the family Coronaviridae, are enveloped RNA viruses that affect humans, mammals and birds, causing both acute and chronic illnesses. Four of the seven known human coronaviruses usually cause a mild coryzal illness only, these are HKU1, NL63, OC43, and...
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Human epididymis protein 4

Human epididymis protein 4 (HE4) is an emerging serum biomarker in the assessment of epithelial ovarian tumors. HE4 is a member of the whey associated protein (WAP) gene cluster and has uncertain biological function 1. Early results indicate that HE4 has higher sensitivity and sensitivity than ...
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Hurthle cell

Hurthle cells are a type of oncocyte arising from thyroid follicular epithelial cells. Pathology Under microscopy, Hurthle cells are larger than typical follicular cells, with abundant mitochondria. Cancers of Hurthle cell origin can be benign adenomas or malignant carcinomas and consist of a...
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Hyperplasia

Hyperplasia is an increase in the number of cells of an organ/tissue, often secondary to a stimulus or stress. This process can be contrasted with hypertrophy, an increase in the size of cells, however these processes frequently co-occur 1. Hyperplasia occurs due to stimulation by growth factor...
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Hypersensitivity reaction

Hypersensitivity reactions are the immunological response to both exogenous and endogenous antigens, and forms the basis for many diseases.  Pathology Classification There are four types of hypersensitivity reactions, each mediated by a different mechanism 1-4: type 1 hypersensitivity: immed...
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Hypertrophy

Hypertrophy is a term describing an increase in the size of cells. It occurs due to an increase in synthesis of intracellular proteins and other cellular components, often in response to an invoking stimulus/stress, which will result in an increase in the size of an organ. This is in contrast t...
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Immunity

The human body regularly encounters harmful microorganisms, and because of this it has developed a system of defenses to help identify and eliminate infective pathogens in the body, known as the immune system. Humans have two types of immunity: innate immunity and acquired immunity. innate imm...
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Immunohistochemistry

Immunohistochemistry is a method of assessing histology with the use of antibodies to specific antigens. It is complementary to the older technique of chemical staining of tissues but is often combined with a counter-stain for context (e.g. hematoxylin to stain cell nuclei blue).  The process e...
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Incubation period

An incubation period is the time between exposure to something pathogenic (including radiation, microbes or chemicals) and when the pathology first becomes apparent by symptoms. Some authors use the terms latent period and incubation period to mean the same period of time. Patients with an infec...
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Inflammation

Inflammation is a response to a noxious stimuli which can be either be acute or chronic. The cardinal signs of inflammation include: heat redness swelling pain loss of tissue function Sub types Acute Inflammation Acute inflammation occurs within the first few hours after an injury. In ...
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Inflammation (acute)

Inflammation is the response of tissues to infection and damage. In the acute phase, it functions to bring cells and molecules to the site of infection or damage to elicit a protective response1.  The acute inflammatory response is characterized by three phases: Dilation of blood vessels, whic...
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Inflammation (chronic)

Chronic inflammation is a prolonged inflammatory response whereby inflammation, injury and repair coexist. It commonly occurs over a period of weeks to months and can follow an acute inflammatory response or begin independently in a slow, insidious manner.  Etiology prolonged infection prolon...
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Intracranial arteries

Intracranial arteries have unique structure when compared to extracranial vessels of similar size: see general histology of blood vessels entry. Proximal larger arteries The proximal arteries, arising from the internal carotid and vertebral arteries have differing distribution of elastic fiber...
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Iodine

Iodine (chemical symbol I) is one of the trace elements. Its biological importance is its central place in the physiology of the thyroid gland and, in radiology, as the key chemical constituent of most of the radiographic, fluoroscopic, and CT contrast media. Chemistry Basic chemistry Iodine ...
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Iron

Iron (chemical symbol Fe) is one of the trace elements that is essential for normal human health due to its central importance in the structure and function of hemoglobin and the cytochromes. Chemistry Basic chemistry Iron is a transition metal with atomic number 26 and an atomic weight of 55...
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Isocitrate dehydrogenase

Isocitrate dehydrogenase (IDH) gene mutations are increasingly being recognized as key genetic prognostic markers for diffuse gliomas, and have been included in a recent (2016) update of diffuse astrocytomas in the WHO classification of brain tumors 7. Somatic mutations of IDH result in enchondr...
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John Cunningham virus

John Cunningham virus, but universally called the JC virus, is a ubiquitous double-stranded DNA virus of the polyomaviridae family 1. In immunocompromised individuals, reactivation can lead to a variety of disease of the central nervous system, the most common of which is progressive multifocal ...
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Kikuchi level

The Kikuchi level is a histopathological term used for describing the degree of infiltration of a sessile early invasive colorectal cancer1. Preoperative assessment of the level of invasion using this classification may decrease the incidence of unnecessary surgery for sessile polyps.  Levels o...
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KRAS mutation

KRAS (shortened name for the gene Kirsten RAt Sarcoma viral oncogene homolog) mutations are associated in a number of malignancies including:  certain adenocarcinomas of the lung colorectal carcinoma 1 pancreatic ductal adenocarcinoma Several germline KRAS mutations have also been found to b...
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Lactate dehydrogenase

Lactate dehydrogenase (LDH or LD) is a key enzyme in most cells, catalyzing the reversible conversion of pyruvate to L-lactate. Its contemporaneous main clinical uses are limited primarily to the investigation of hemolysis, serous collections and as a tumor marker. Physiology L-lactate dehydro...
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Lamellated

The term lamellated (or laminated which means the same thing) is a radiopathological term used to describe the layered appearance of many calculi, including those of the renal tract, the salivary glands, and the biliary tree. The internal structure of these calculi has been likened to that of an...
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Langerhans cell

Langerhans cells are dendritic cells of monocyte-macrophage lineage, containing large granules called Birbeck granules. They are normally found in epithelial surfaces, lymph nodes and other organs, and can also be found elsewhere, particularly in association with Langerhans cell histiocytosis. ...
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Lead

Lead (chemical symbol Pb) is a toxic metallic element with no known biological function in humans. Chemistry Basic chemistry Lead is one of the post-transition metals with the atomic number 82 and atomic weight 207.2. It is greyish in color and is pliable, poorly electrically-conducting with ...
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Lipase

Lipase, more specifically pancreatic lipase, is an enzyme produced in the pancreas and is responsible for the digestion of fat molecules. It may be raised (hyperlipasemia) in numerous pancreatic, hepatobiliary and other diseases but is most commonly associated with acute pancreatitis. Physiolog...
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Lipohyalinosis

Lipohyalinosis is a disease affecting the small cerebral arteries associated with lacunar infarction and deep white matter changes related to small vessel chronic ischemia. Pathology The histopathological landmarks of lipohyalinosis are irregular fibrosis and hyaline of small cerebral arteries...
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Liquefactive necrosis

Liquefactive necrosis is a form of necrosis where there is transformation of the tissue into a liquid viscous mass. Pathology In liquefactive necrosis, the affected cell is completely digested by hydrolytic enzymes leading to a soft, circumscribed lesion which can consist of fluid with remains...
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Lymph

Lymph (also known as lymphatic fluid) is the name given to the interstitial fluid once it has passed into the lymphatic vessels. Formation As blood passes through capillary beds a significant proportion of the plasma is filtered into the extracellular space. Most of this filtered tissue fluid ...
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Macroamylasemia

Macroamylasemia is the presence of serum amylase of a large molecular size, seen in both otherwise healthy individuals, and also in various diseases. Amylase seems to be able to self-polymerize and/or form complexes with other blood proteins, e.g. immunoglobulins. Epidemiology Macroamylasemia ...
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Macrolipasemia

Macrolipasemia is the presence of serum lipase of a large molecular size, seen occasionally in otherwise healthy individuals, but more commonly in various diseases. Lipase is able to self-polymerize and/or form complexes with other blood proteins e.g. immunoglobulins. Epidemiology Epidemiologi...
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Macromolecular complex

Macromolecular complexes include both macrohormones and macroenzymes, which consist of hormones and enzymes respectively covalently bound to carrier molecules, e.g. immunoglobulins, or occasionally the molecule may self-polymerize. Their primary importance lies in their ability to produce an art...
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Malignant transformation

Malignant transformation is the term given to the process whereby either normal, metaplastic, or benign neoplastic tissue, becomes a cancer. The process usually occurs in a series of steps and the affected tissue gradually accumulates the genetic mutations that express a malignant phenotype. The...
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Mammalian target of rapamycin

The mammalian target of rapamycin (mTOR), also known as mechanistic target of rapamycin, are two proteins that are involved in cell signaling pathways implicated in tumorigenesis. The mTOR proteins are serine/threonine protein kinases that combine with several other proteins to form two large c...
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Manganese

Manganese (chemical symbol Mn) is one of the essential trace elements. It has an important biological role in the synthetic pathway for mucopolysaccharides, and it also is a cofactor for several enzymes. Chemistry Basic chemistry Manganese has the atomic number 25 with an atomic weight of 54....
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MAPK pathway

The MAPK pathway (mitogen-activated protein kinase pathway) also known as the RAS/MAPK pathway is an oncogenic pathway and is most commonly involved in human cancers.  It consists of a membrane receptor tyrosine kinase which when bound to by a growth factor results in activation of the signal t...
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Maternal serum alpha fetoprotein (MSAFP)

Maternal serum alpha fetoprotein (MSAFP) is a screening test that examines the level of alpha fetoprotein (AFP) in a pregnant woman. AFP is produced by both the yolk sac and foetal liver during pregnancy. Indications Ideally, all pregnant women should undergo the screening test between 15-20 w...
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Mercury

Mercury (chemical symbol Hg) is a liquid metallic element that historically was used in many medicines, but is now restricted due to legitimate concerns about mercury poisoning. Chemistry Basic chemistry Mercury is a silvery liquid at standard temperature and pressure. It has the atomic numbe...
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Metaplasia

Metaplasia is a general pathology term that refers to process when one cell type is replaced by another. It usually occurs in the context of a changed cellular environment to which the new cell type is better adapted 1. Examples include 2-5: Barrett esophagus: normal squamous epithelium replace...
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Microglia

Microglia is one of the four types of glial cell and are the central nervous system equivalent of monocyte-macrophage system 1,2. During health, they are essentially inactive with small cell bodies and numerous processes extending throughout the local parenchyma 1,2. When presented a condition w...
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Micrometastasis

Micrometastases are defined by the UICC TNM Classification of Malignant Tumors as conglomerations of tumor cells measuring between 0.2 mm and 2 mm in size. Clusters of cells sized less than 0.2 mm in maximal dimension are termed isolated tumor cells (ITCs). Tumor clusters measuring larger than 2...
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Molybdenum

Molybdenum (chemical symbol Mo) is one of the essential trace elements. It complexes with a molecule called molybdopterin to form molybdenum cofactor, essential for the functioning of several important metabolic enzymes.  Chemistry Basic chemistry Molybdenum has the atomic number 42, with an ...
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Monomelic

Monomelic is typically used to refer to a condition that is confined to only one limb. Examples of conditions that can be monomelic include fibrous dysplasia and melorheostosis. See also monostotic polyostotic monomelic
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Monostotic

Monostotic is typically used to refer to a condition that involves only one bone. Examples of conditions that can be monostotic include fibrous dysplasia and melorheostosis. See also monostotic polyostotic monomelic
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Multilocular cystic renal neoplasm of low malignant potential

Multilocular cystic renal neoplasm of low malignant potential is a low-grade adult renal tumor composed entirely of numerous cysts. The entity was previously known as multilocular cystic renal cell carcinoma, which usually had clear cell morphology, but was redefined in the 2016 WHO classificati...
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Mycobacterium tuberculosis

Mycobacterium tuberculosis is a thin, slightly curved bacillus. A member of the Mycobacterium tuberculosis complex, it is an obligate aerobic bacterium that is the etiologic agent of the majority of tuberculosis cases.  Epidemiology The worldwide incidence of tuberculosis was 8.7 million in 20...
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Myo-inositol peak

Myo-inositol is one of the compounds images with MR spectroscopy (MRS) at both 1.5 T and 3 T and is seen to resonate at 3.5 ppm chemical shift (right of the choline peak).  Myo-inositol is a precursor of both phosphatidylinositol (the major inositol-containing phospholipid) and of phosphatidyli...
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Naming of organisms

Occasionally, we will refer to lifeforms in an article or case, and we adhere to standard scientific convention when it comes to naming organisms. as set down by the International Commision on Zoological Nomenclature (ICZN) 1. As per the standard binomial system, the genus and species of the org...
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Necrosis

Necrosis (plural: necroses) is defined as unregulated cell death. This is in contrast to apoptosis, which is a form of regulated, or programmed, cell death 1.  Necrosis is the most common type of cell death observed in injury/disease. It occurs when cellular damage is so severe that lysosomal e...
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Neuritic plaques

Neuritic plaques (also known as senile plaques) are pathological extracellular aggregates formed around a core of amyloid β peptide and are a hallmark of Alzheimer's disease.  They should not be confused with neurofibrillary tangles which are intracytoplasmic. Pathology Neuritic plaques are e...
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Neurofibrillary tangles

Neurofibrillary tangles (NFTs) are abnormal cytoplasmic accumulations of tau proteins, found in neuronal and glial cells of the central nervous system. They are responsible for a number of neurodegenerative diseases (collectively known as tauopathies) including 1: progressive supranuclear palsy...
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Neurofibromin

Neurofibromin is a protein coded for by the NF1 gene located on chromosome 17 (17q11.2). It is a multifunctional protein and is involved in the regulation of many cellular signaling pathways. In patients with a mutation of the NF1 gene, neurofibromin is defective and results in the clinical synd...
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Neuron

Neurons are cells of the central nervous system, located within the grey matter, and responsible for all neurological functions of the brain.  Structure Neurons vary in morphology and size substantially, but all share a number of features 1: a cell body nucleus perikaryon: cytoplasm surroun...
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Nitrogen

Nitrogen (chemical symbol N) is one of the basic organic elements, and is a key constituent of amino acids, the building blocks of proteins, and of nucleic acids (i.e. DNA and RNA). On earth it is the most abundant element found in its pure form, and comprises 78% of all breathable air.  Chemis...
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Edema

Edema is the accumulation of fluid in tissues. It is caused by an imbalance between forces holding fluids in the vasculature and tissues 1. Fluids are normally held in a steady state between tissues and vasculature by homestasis between these forces (Starling equation) 2: capillary hydrostatic ...
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Oligodendrocytes

Oligodendrocytes are one of the four principles types of glial cells and are the central nervous system equivalent of the Schwann cells found peripherally. They wrap the neurons of the brain and spinal cord with myelin 1.  See also oligodendroglioma
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Opportunistic infection

Opportunistic infections (OI) are caused by micro-organisms (sometimes called opportunists) that under normal circumstances do not cause infections, but in certain clinical contexts, most commonly immunosuppression, may become pathogenic 1.
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Osteitis

Osteitis is an inflammation of the bone. This inflammation is often caused by bacterial infections but may be idiopathic. Terminology Osteitis refers only to the inflammation of bony structures, in particular the cortex (non-medullary infection) 1,2. If there is an additional inflammatory invo...
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Oxygen

Oxygen (chemical symbol O) is one of the basic organic elements, and is a constituent of most of the known organic molecules - and therefore all lifeforms - on earth.  Chemistry Basic chemistry Oxygen is a colourless odorless diatomic gas with an atomic number 8 and atomic weight 15.999. It h...
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p16

p16 is a widely used immunohistochemical marker indicating expression of the cell cycle protein cyclin-dependent kinase inhibitor 2A, which is upregulated by human papillomavirus (HPV) infection. In the uterine cervix, p16 positivity supports the diagnosis of a high-grade squamous intraepithelia...
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Pandemic

A pandemic is applied to an outbreak of disease that has spread across the globe, or in other words, an epidemic that has crossed many regions, borders and multiple continents. Some of the largest pandemics in history include the bubonic plague in the 14th century and the Spanish influenza of th...
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Pathology curriculum

The pathology curriculum is one of our curriculum modules and aims to be a collection of articles that represent the core pathology knowledge for radiologists and other imaging professionals: general pathology cellular pathology ​pathologic classification systemic pathology pathology of the...
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Perivascular pseudorosettes (ependymoma)

Perivascular pseudorosettes are a common histologic feature of central nervous system ependymomas. They represent sections through papillary structures composed of tumor cells arranged radially around a central vessel. Between the central vessel and the tumor cells is a relatively microscopicall...
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Phlegmon

Phlegmon (plural: phlegmons) refers to unbounded, non-specific inflammation of soft tissue, usually in the context of infectious disease. It is distinct from an abscess which is walled-off by peripheral granulation tissue. Terminology Both historically and contemporaneously, phlegmon is used i...
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Pick bodies

Pick bodies are intracytoplasmic spherical inclusions found in Pick's disease. They are composed of tau fibrils (thus Pick's disease is a tauopathy) arranged in a disorderly array 1. Although tau protein is a major component a number of other protein products are present, including ubiquitin and...
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Picornaviruses

Picornaviruses (pico-RNA-viruses) are non-enveloped, positive-stranded RNA viruses with an icosahedral capsule. Their positive, single stranded RNA architecture places them in Baltimore group IV. The name derives from the fact that they are small (pico) RNA viruses. The picornavirus family cont...
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Pneumolabyrinth

Pneumolabyrinth refers to the presence of gas within the inner ear and is a sign of perilymphatic fistula in a trauma setting. It manifests in HRCT of the temporal bone as air bubbles in the cochlea, the vestibule or the semicircular canals. Epidemiology It's not a rare finding following tempo...
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Poliovirus

Poliovirus is the causative agent involved in poliomyelitis. It is a single-stranded RNA virus and one of the smallest significantly described viruses: group: group IV family: picornaviruses genus: enterovirus species: enterovirus C subtype: poliovirus Related pathology poliomyelitis pol...
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Polyostotic

Polyostotic is term used to describe a condition involving multiple bones. Examples of conditions that can be polyostotic include fibrous dysplasia and melorheostosis. See also monostotic monomelic
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Pregnancy-associated plasma protein-A

Pregnancy-associated plasma protein-A (PAPP-A) is a protein found in the maternal circulation and is produced by the placenta. The PAPP-A gene has been assigned to human chromosome 9q33.1 and contains 22 exons 5. PAPP-A values tend to rise exponentially during pregnancy and the reference range d...
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Primary lung tumors in children

Pediatric primary lung tumors are rare in children however they must be distinguished from locally aggressive inflammatory conditions and benign disease. 1 Primary lung tumors in the neonates and infants include: pleuropulmonary blastoma (PPB) infantile fibrosarcoma of the lung fetal lung in...
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Primary pulmonary enteric adenocarcinoma

Pulmonary enteric adenocarcinoma (PEAC) or pulmonary adenocarcinoma with enteric differentiation (PAED) is an extremely rare variant of primary invasive adenocarcinoma of the lung. It has morphological and immunohistochemical profiles overlapping with that of colorectal carcinoma. Due to this, i...
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Probabilistic atlas

Probabilistic atlases, also known as probability maps, are anatomical or anatomopathological atlases based on statistically-weighted composites of many specimens. Traditional anatomy atlases were based on one or a few specimens sometimes with common variations indicated or shown. Probabilistic a...
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Programmed death-ligand 1 (PD-L1)-targeted monoclonal antibodies

Programmed death-ligand 1 (PD-L1)-targeted monoclonal antibodies interact with a protein called PD-1 on T-cells and can be useful in determining if certain immunomodulation therapies can be used in treatment of certain types of cancers. PD-L1 is a major immune checkpoint protein that mediates an...
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Prostate specific antigen

Prostate specific antigen (PSA) is currently used as a tumor marker for prostate adenocarcinoma. PSA is a 33 kilodalton glycoprotein produced in prostate epithelial cells. Its normal physiologic role is as a liquefying agent for seminal fluid; only a tiny amount leaks into the blood, therefore ...
Article

Prostate-specific membrane antigen

Prostate-specific membrane antigen (PSMA) (also known as glutamate carboxypeptidase II) is a type II transmembrane glycoprotein that has become an increasingly prominent imaging biomarker 1. PSMA has emerged as a useful target in PET imaging of prostate cancer, especially in the evaluation of sm...
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Proteins

Proteins comprise long chains of amino acids joined together by peptide bonds. Structure A peptide bond is formed by the carboxyl group of one amino acid linking to the amino group of the next one.  Arbitrarily proteins are categorized according to length of the amino acid chain: peptides (2-...
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PSA density

The PSA density (PSAD), is a calculation performed at diagnosis and is the serum PSA level (ng/mL) divided by the volume of the prostate gland (mL)1. Prostate volume is calculated from TRUS measurements2,3.  Alternatively, PSAD may be calculated using MRI measurements3 of prostate volumes or le...
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Pseudocyst

A pseudocyst is an abnormal fluid-filled cavity which is not lined by epithelium.  It is this fact that distinguishes it pathologically from a cyst, which is lined by epithelium. Examples of pseudocysts include: adrenal pseudocyst auricular pseudocyst meconium pseudocyst pancreatic pseudocy...
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Pulmonary Acinetobacter infection

Pulmonary Acinetobacter infection refers to pulmonary infection with Acinetobacter species of which Acinetobacter calcoaceticus-A baumannii complex accounts for a considerable proportion. Pulmonary infection with this organism can cause hospital acquired pneumonia (especially the late onset type...
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Pulmonary blastoma

Pulmonary blastomas (PBs) comprise a rare group of lung tumors principally consisting of immature mesenchymal and epithelial structures that structurally mimic the embryonic lung. Traditionally they were classified as well-differentiated fetal adenocarcinoma (WDFA) of lung - now considered rem...
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Pulmonary infiltrates

The term pulmonary infiltrate is considered a context-dependent, non-specific and imprecise descriptive term when used in radiology reports (plain film or CT). From a pathophysiological perspective, the term "infiltrate" refers to “an abnormal substance that accumulates gradually within cells o...
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Pulmonary interstitial edema

Pulmonary interstitial edema represents a form of pulmonary edema resulting from pathological fluid buildup in the interstitial spaces due to increased hydrostatic driving pressure. Pathology Interstitial lung edema arises almost exclusively due to an increase of the pulmonary capillary hydros...
Article

Reed-Sternberg cells

Reed-Sternberg cells are a classical finding diagnostic of Hodgkin lymphoma. They are giant, multinucleated cells with abundant pale cytoplasm. Reed-Sternberg cells are rare, making up <1% of lymphoid tissue, with the background consisting of lymphocytes, plasma cells, eosinophils and macrophages.
Article

Retroclival hematoma

Retroclival hematoma is a collection of blood located along the dorsum sellae, the clivus and could reach the dens. It have been classified into epidural retroclival hematoma and subdural retroclival hematoma depending on the anatomical location of the blood accumulation.  Epidemiology It's an...
Article

Rheumatoid factor

Rheumatoid factor (RF) is an immunoglobulin initially described in association with rheumatoid arthritis. It is an IgM antibody against the FC portion of the IgG antibodies. Ongoing research has identified a group related immunoglobulins, classed as rheumatoid factors (RFs) and despite extensive...
Article

ROS1 mutation

The ROS1 mutation is a mutation occurring in the ROS1 oncogene on chromosome 6 resulting in a defective receptor tyrosine kinase which has structural similarity to the anaplastic lymphoma kinase (ALK) protein. It is thought to be present in several cancers of the subtype non-small cell lung can...
Article

Rosenthal fibers

Rosenthal fibers are astrocytic cytoplasmic inclusions, typically found in areas of longstanding gliosis. These elongated or "corkscrew" structures occur within astrocytic processes and are brightly eosinophilic (stain bright pink on the H&E stain) 1-3. They represent astrocytic processes swolle...
Article

S100

S100 is a family of cytoplasmic calcium-binding proteins expressed in numerous cell lines which can be targeted by immunohistochemistry. Staining for S100 is helpful in characterizing a number of tumors, including malignant melanoma, glial tumors, neurogenic tumors (e.g. schwannomas and neurofib...
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Schiller-Duval body (histology)

Schiller-Duval body is a perivascular structure that can be found in 50% of testicular yolk sac tumors also known as endodermal sinus tumors. If present it is considered pathognomonic.  Pathology A central vessel is surrounded by tumor cells, and the cell-vessel complex is contained in a cysti...
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Scientific notation

In general, the Radiopaedia style guide adheres to internationally-agreed standards for scientific notation. The main exception is isotope notation, for which we have decided to drop the use of superscripted mass numbers. anatomic nomenclature chemical element notation genes and proteins nam...

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