14-3-3 protein is found in the cerebrospinal fluid (CSF), and is currently used to help identify patients with sporadic Creutzfeldt-Jakob disease (sCJD).
In diagnosing sCJD, the sensitivity of 14-3-3 protein is 92% and its specificity is 80% 1. A negative 14-3-3 assay may be helpful in reducin...
1p19q codeletion stands for the combined loss of the short arm chromosome 1 (i.e. 1p) and the long arm of chromosome 19 (19q) and is recognised as a genetic marker predictive of therapeutic response to both chemotherapy and combined chemoradiotherapy and overall longer survival in patients with ...
2-hydroxyglutarate is a metabolite that accumulates in the brains of patients with IDH-1 mutated (IDH-1 positive) brain tumours, particularly diffuse low-grade gliomas. Although not in widespread clinical use, it is likely that 2-hydroxyglutarate, which resonates at 2.25 ppm, will be able to be ...
The adenoma-carcinoma sequence refers to a stepwise pattern of mutational activation of oncogenes (e.g. K-ras) and inactivation of tumour suppressor genes (e.g. p53) that results in cancer. An oncogene is a gene that has the potential to cause cancer. In tumour cells, these are often mutated or ...
Human AFP (alpha-fetoprotein) reduction is seen in pregnancy where it can be associated with:
certain chromosomal anomalies
Cornelia de-Lange syndrome 2
Alzheimer type I glia are a type of glial cell. They are large multinucleated astrocytes encountered in glial tumours and progressive multifocal leukoencephalopathy (PML) 1.
Alzheimer type II glia are a type of glial cell. They are a pathological reactive astrocyte seen in the brain, unrelated to Alzheimer disease. They are seen most frequently in Wilson disease, but also in other systemic metabolic disorders, particularly those with elevated ammonia levels, typical...
Aspergillus clavatus is one of the species of Aspergillus that can cause pathology in humans. It is allergenic and causes a hypersensitivity pneumonitis called malt-workers lung.
Astrocytes are cells of the central nervous system which act as both physical and physiological support for the neurones that are embedded between them. They are particularly abundant in the grey matter, where they are the most abundant glial cells 1.
They are highly branched and contribute to ...
Atypical small acinar proliferations (ASAP) are premalignant lesions of the prostate, which can be found in as many as 5% of prostate biopsies. They are suspicious glands without adequate histologic atypia to establish a definitive diagnosis of prostate cancer. Some studies showed that there is ...
Serum CA-125 is well recognised as an ovarian cancer-associated marker and is an antigen determinant on a high-molecular-weight glycoprotein. The normal range of CA-125 is 0-35 U/mL.
Serum CA-125 levels can also be used to monitor the response to treatment as well as a prognostic indicator sinc...
CA 19-9 (carbohydrate antigen 19-9 or cancer antigen) is a serum antigen (monosialoganglioside) that has increased diagnostic use in the management of several malignancies, mainly of hepatopancreaticobiliary origin. It is non-specific, however, and can rise in both malignant and non-malignant co...
Serum carcinoembryonic antigen (CEA) is a cell-adhesive glycoprotein that was discovered in colorectal cancer in 1965, and is hence one of the oldest and most used tumour markers. Its name derives from its normal expression in fetoembryonic liver, gut and pancreas tissue.
Normal range of CEA is...
Charcot-Leyden crystals consist of collections of bipyramidal crystalloid made up of eosinophilic membrane proteins, which occur in:
other eosinophilic lung disease 2
certain cases of sinusitis (e.g. allergic fungal sinusitis)
They may be detected in the sputum or sinus secretions wi...
A choristoma is simply a collection of microscopically normal cells or tissues in an abnormal location. This is different to a hamartoma which is derived only from local tissues.
adrenal choristoma (myelolipoma)
facial nerve choristoma
Chromogranin A (CgA) is an acidic secretory glycoprotein found in the secretory granules of neuroendocrine cells and neurones, as is a member of the granin family of proteins. It can be used both for immunohistochemical stains and as a serum marker 4.
Chromogranin A is us...
The circumferential resection margin (CRM) is a term used in rectal carcinoma excision surgery (such as total mesorectal excision (TME)).
Pathologic evaluation of the resection margin on the excised rectum has been considered important for determining the risk of local recurrence. A margin of ≤...
Columnar alteration with prominent apical snouts and secretions (CAPSS) is a pathological entity encountered when breast biopsies are done for investigation of punctate or amorphous calcifications. CAPSS involves the terminal ductal and lobular units (TDLU's).
It is sometimes classified under t...
Cowdry bodies are neuronal intranuclear inclusions seen in Herpes simplex virus infections.
Cushing syndrome is due to the effects of excessive glucocorticoids which may be exogenous or endogenous.
In modern Western populations, iatrogenic steroid administration for treatment of inflammatory condition is the most common cause, e.g. asthma, rheumatoid arthritis.
Ependymal cells are one of the four main types of glial cells, and themselves encompass three types of cells 1:
ependymocytes: line the ventricles of the brain and central canal of the spinal cord
tanycytes: line the floor of the third ventricle
choroidal epithelial cells: line the surface o...
Ependymal rosettes correspond to a histologic architectural pattern that very characteristic of ependymomas, as tumour cells form structures similar to the lining of normal ventricles. They are characterised by a halo or spoke-wheel arrangement of tumour cells surrounding an empty central tubule...
Ependymocytes are one of the three types of ependymal cells, which in turn are one of the four principles types of glial cells, and are found lining the ventricular system of the brain and the central canal of the spinal cord 1.
They do not form a water-tight barrier between the cerebral spina...
Epithelial membrane antigen (EMA) is a commonly used target for immunohistochemisty, found on the surface of many epithelial cells and thus present in a wide variety of tumours. It also is sometimes seen within the cytoplasm of cells (e.g. perinuclear dot in ependymomas).
Extensive intraductal component (EIC) in breast imaging evaluation is the pathological description where an invasive ductal carcinoma has a prominent intraductal component within it or if there is intraductal carcinoma, DCIS is present within sections of normal adjacent tissue. It is sometimes c...
Faecal calprotectin (FCAL) is a protein which is a marker of inflammation of the gut used as a diagnostic tool and marker of disease activity for Crohn disease and ulcerative colitis.
Calprotectin is a protein complex from the S-100 family, which is formed of three polypeptide cha...
Fibrillary astrocytomas are the most common type of diffuse low grade astrocytoma and as of the 2016 update to WHO classification of CNS tumours it no longer exists as a distinct entity, having been incorporated into the generic term diffuse astrocytoma 6.
Unlike the other variant...
The presence of Flexner-Wintersteiner rosette is characteristic for retinoblastoma but is also seen in pineoblastoma and medulloepitheliomas.
Fracture healing occurs naturally after traumatic bony disruption. This process begins with haemorrhage and progresses through three stages:
This process can be supported by various treatment options with immobilisation a mainstay; inappropriate treatment ...
Gallbladder volvulus is a relatively rare condition in which there is a rotation of the gallbladder around the axis of the cystic duct and artery.
Symptoms are non-specific, however right upper quadrant pain and vomiting are similar to biliary colic. Laboratory evaluation...
Gallstone pancreatitis refers to pancreatitis caused by gallstones, specifically distal choledocholithiasis. Gallstones is the cause for 35-40% of acute pancreatitis but this number has a wide regional variance.
Gallstone pancreatitis has a higher incidence in women (compared to ...
Gallstones, also called cholelithiasis, are concretions that occur anywhere within the biliary system, most commonly within the gallbladder.
Gallstones (cholelithiasis) describes stone formation at any point along the biliary tree. Specific names can be given to gallstones dependi...
Gamma-aminobutyric acid (GABA) is the principle inhibitory neurotransmitter in the central nervous system 1 and as such, is one of the compounds examined in MR spectroscopy. It is present in the human brain at a concentration of about 1 mM, a whole order of magnitude lower than some of the more...
Ganglioneuromas are fully differentiated neuronal tumours that do not contain immature elements and potentially occur anywhere along the peripheral autonomic ganglion sites.
On imaging, usually, they present as well-defined solid masses and can be quite large at presentation. Generally, they a...
Gangrenous cholecystitis is the most common complication of acute cholecystitis, affecting ~15% (range 2-30%) of patients.
Gangrenous cholecystitis occurs as a result of ischaemia with necrosis of the gallbladder wall 4.
Gartner duct cysts develop from embryologic remnants of the Wolffian (mesonephric) duct. They are often noticed incidentally on ultrasound or MRI.
They may cause mass effect on adjacent structures.
Gartner duct cysts are located in the anterolateral ...
Gastric adenocarcinoma, commonly referred to as gastric cancer, refers to a primary malignancy arising from the gastric epithelium. It is the most common gastric malignancy.
Gastric cancer is rare before the age of 40, but its incidence steadily climbs after that and peaks in the...
Gastric antral vascular ectasia (GAVE), also known as watermelon stomach, is a rare condition affecting the stomach. It is one of the diagnoses to consider in older patients with severe anaemia and occult or profuse gastrointestinal bleeding (especially in those with cardiac, liver, or renal dis...
Gastric antral webs are a ring of mucosa in the distal stomach (gastric antrum) that can lead to gastric outlet obstruction. A circumferential ring of mucosa has also been termed a "gastric antral diaphragm".
Gastric antral webs are rare. There is an association with trisomy 21 an...
Gastric lipomas are a location-specific subtype of gastrointestinal lipomas and represent a rare benign mesenchymal tumours of the stomach. They can be definitively diagnosed on CT.
Gastric lipomas are rare, accounting for <5% of gastrointestinal lipomas and <1% of all gastric ne...
Gastric polyps are uncommon findings, even on endoscopy where they are encountered in only 2-6% of patients.
There are a number of gastric polyp subtypes 1-3:
virtually no malignant potential
typically small (<1cm), multiple, and sessile...
Gastric volvulus is a specific type of volvulus that occurs when the stomach twists on its mesentery. It should be at least 180° and cause bowel obstruction to be called gastric volvulus. Merely gastric rotation on its root is not considered gastric volvulus.
Gastrinomas are the second most common pancreatic endocrine tumour and the most common type in the setting of multiple endocrine neoplasia type I (MEN I).
Most gastrinomas are sporadic, although some are seen in the setting of multiple endocrine neoplasia type I (MEN I). In genera...
Gastrointestinal amyloidosis is relatively common, although symptomatic involvement is more rare. It is diagnosed if there is persistent gastrointestinal (GI) symptoms with endoscopic biopsy proven amyloid deposition.
Tends to affect middle-aged and older patients.
Gastrointestinal angiodysplasias or angioectasias are one of the most common causes of occult gastrointestinal bleeding.
Patients can present with symptoms and signs upper or lower gastrointestinal bleeding although they can commonly be an incidental finding.
Gastrointestinal neuroendocrine tumours (GI NETs) can be functional or non-functional:
functional NETs can be challenging to localise as:
they are often small in size at the time of diagnosis
arise in many sites throughout the body
non-functioning and/or malignant NETs often are larger at ...
Gastro-oesophageal reflux disease (GORD) is a spectrum of disease that occurs when gastric acid refluxes from the stomach into the lower end of the oesophagus across the lower oesophageal sphincter (LOS).
Minor reflux disease
In most patients with reflux disease, reflux is initiated...
Gastroschisis refers to extra-abdominal herniation (evisceration) of fetal or neonatal bowel loops (and occasionally portions or the stomach and or liver) into the amniotic cavity through a para-umbilical abdominal wall defect.
The estimated incidence is at around 1-6 per 10,000...
GATA2 deficiency is a germ-line disease expressed as a wide spectrum of phenotypes, including monocytopenia, myelodysplasia, myeloid leukaemias, and lymphoedema. It is a rare cause of pulmonary alveolar proteinosis.
GATA2 deficiency has considerably variable clinical mani...
Gaucher disease (GD) is the most common lysosomal storage disease in humans. It is an autosomal recessive, multisystem disease arising from a deficiency of glucocerebrosidase or beta-glucosidase activity, resulting in accumulation of a glycolipid (glucocerebroside) within the lysosomes of macrop...
Gel bleed is a phenomenon associated with silicone breast implants.
Gel bleed refers to microscopic diffusion of silicone gel through the breast implant elastomer shell. The implant shell, made of silicone, is a semipermeable membrane that allows for the egress or bleed of silicone n...
Gemistocytic astrocytoma is a histologic subtype of low grade astrocytoma, with a poorer prognosis than other matched WHO grade tumours, and with no specific imaging features.
For a general discussion of clinical presentation, epidemiology, treatment please refer to the article on low grade as...
Geophagy is the intentional ingestion of earth, soil or clay and is a form of pica. This practice is not uncommon in the southern regions of the United States or provinces of Africa. It may be seen in pregnant or iron-deficient patients 3. Although geophagia may be seen in the context of a varie...
Germinal matrix haemorrhages, also know as periventricular-intraventricular haemorrhages (PVIH), correspond to the most common type of intracranial haemorrhage in neonates and are related to a perinatal stress affecting the highly vascularised subependymal germinal matrix. The majority of cases ...
The term germinoma usually refers to a tumour of the brain (WHO Classification of CNS tumours), but can also refer to similar tumours of the ovary and testis.
dysgerminoma of the ovary
seminoma of the testis
All three tumours share similar histology.
Gerstmann-Straussler-Scheinker disease is a very rare type of human transmissible spongiform encephalopathy. It manifests with dementia and/or ataxia and is due to a mutation in the prion protein (PRNP) gene, which is inherited in an autosomal dominant pattern.
Gerstmann syndrome, also known as angular gyrus syndrome, is a dominant hemisphere stroke syndrome consisting of four components:
agraphia or dysgraphia
acalculia or dyscalculia
Pure Gerstmann syndrome is said to be without aphasia.
History and ety...
Gestational choriocarcinoma (GC) is a type of choriocarcinoma that follows a gestational event. Similar to choriocarcinomas in general, it lies at the malignant end of the spectrum of gestational trophoblastic disease.
Approximately 50% of gestational choriocarcinomas arise from a pr...
Giant cell glioblastoma is a variant of glioblastoma (along with epithelioid glioblastoma and giant cell glioblastoma) recognised in the current (2016) WHO classification of CNS tumours 7. This tumour was previously called monstrocellular tumour due to the macro size of its cells.
Giant cell tumours of the tendon sheath (GCTTS), also known as pigmented villonodular tumour of the tendon sheath (PVNTS) or extra-articular pigmented villonodular tumour of the tendon sheath, are uncommon and usually benign lesions that arise from the tendon sheath. It is unclear whether these ...
Giant cerebral aneurysms are ones that measure >25 mm in greatest dimension.
Giant cerebral aneurysms account for ~5% of all intracranial aneurysms 1,3. They occur in the 5th-7th decades and are more common in females 2.
Patients can present with symptoms ...
Giant fibroadenomas are fibroadenomas weighing more than 500 grams or measuring >5 cm in size 2. They are usually encountered in pregnant or lactating women.
Gigantomastia (or macromastia) is a term given when there is massive breast enlargement. It is often associated with pregnancy.
Gigantomastia is a very common condition characterised by proliferation of either breast fatty tissue or glandular tissue or both, resulting in rapid increase in breas...
Glial cells, or neuroglia, are cells that surround the neurones of the central nervous system embedded between them, providing both structural and physiological support 1-3. Together they account for almost half of the total mass 1 and 90% of all cells of the central nervous system 3.
Glial fibrillary acid protein (GFAP) is a commonly used target for immunohistochemistry and is positive in many glial cells and tumours of glial origin. GFAP is the building block for intermediate filaments which are abundant in the cytoplasms particularly of astrocytes.
Gliomatosis cerebri is a rare growth pattern of diffuse gliomas that involves at least three lobes by definition. There often is an important discordance between clinical and radiological findings, as it may be clinically silent while it appears as a very extensive process radiologically.
Gliosarcomas are a variant of glioblastoma (along with epithelioid glioblastoma and giant cell glioblastoma) recognised in the current (2016) WHO classification of CNS tumours 9. They are highly malignant (WHO grade IV) primary intra-axial neoplasms with both glial and mesenchymal elements.
Gliosis is the focal proliferation of glial cells in the CNS in response to insult. By strict definition, gliosis is not synonymous with encephalomalacia which is the end result of liquefactive necrosis of brain parenchyma following an insult. Radiologically they share similar features and is of...
Globe rupture is an ophthalmologic emergency. A ruptured globe or an open-globe injury must be assessed in any patient who has suffered orbital trauma because open-globe injuries are a major cause of blindness.
In a blunt trauma, ruptures are most common at the insertions of the intraocular mus...
Globus pharyngeus is the subjective feeling of a lump in the throat which can have a variety of causes. In modern practice globus is often evaluated by flexible nasoendoscopy in the first instance since many patients present to otolaryngology services. If no cause is identified or if nasoendosco...
Glomus tympanicum paragangliomas (chemodectomas) are the most common middle ear tumour.
There is a female predominance (M:F = 1:3); presentation is most common when patients are more than 40 years old 1,2.
May be incidental but symptomatic masses produce ...
Glucagonomas are pancreatic endocrine tumours that secrete glucagon. Most lesions are malignant.
They are rare with an incidence of 0.000005%. Equal incidence in middle-aged men and women.
Most patients present with a necrolytic migratory rash and various ...
Gluteal injection site granulomas are a very common finding on CT and plain radiographs. They occur as a result of subcutaneous (i.e. intra-lipomatous) rather than intramuscular injection of drugs, which cause localised fat necrosis, scar formation and dystrophic calcification.
Once familiar wi...
Gnathic osteosarcoma is a subtype of osteosarcoma that primarily affects the mandible (horizontal ramus) and maxilla (alveolar ridge, sinus floor, and palate).
represents ~6% of osteosarcomas 3
60% in males
has an older onset (~30 years) and a peak incidence: 30-40 years
Goitre refers to enlargement of the thyroid gland. It can occur from multiple conditions.
The definition of a goitre depends on age and sex; below are the upper limits of normal for thyroid gland volume 1:
adult males: 25 mL
adult females: 18 mL
13-14 years: 8-10 mL
3-4 years: 3 mL
The Gosselin fracture is a fracture of the distal tibia with a V-shaped fractured fragment and intra-articular involvement.
History and etymology
It is named after Leon Athanese Gosselin (1815–1887), a French surgeon.
A gossypiboma, also called textiloma or cottonoid, refers to a foreign object, such as a mass of cotton matrix or a sponge, that is left behind in a body cavity during an operation. It is an uncommon surgical complication.
The manifestations and complications of gossypibomas are so variable tha...
Gout is a crystal arthropathy due to deposition of monosodium urate (MSU) crystals in and around the joints.
Typically occurs in those above 40 years. There is a strong male predilection of 20:1.
Characterised by monosodium urate crystals deposition in periarticular so...
Graft versus host disease (GvHD) is a frequent complication of allogeneic post haematopoietic stem cell transplantation (HSCT), commonly known as bone marrow transplantation. Anti-rejection drugs have reduced the incidence, although it does still frequently occur.
GvHD can present e...
Pulmonary graft versus host disease (GvHD) is one of the thoracic manifestations that can complicate haematopoetic stem cell transplantation. Pulmonary GvHD can be broadly divided into acute and chronic disease 1-4:
acute pulmonary GvHD
pulmonary involvement is rare
the median time of onset o...
A granular cell tumour (GCT) of the breast is an uncommon, usually benign tumour which is possibly of neural origin.
They tend to occur at a younger age than other types of breast cancer 4. The age range of presentation, however, can be very variable although they occur more commo...
Granular cell tumour of the pituitary region, also known as a pituitary choristoma, are rare low-grade tumours of the posterior pituitary and infundibulum.
Care must be taken when reading older literature as granular cell tumours of the pituitary region, and alternative names incl...
Granulocytic sarcoma (also called myeloid sarcoma and chloroma) is a rare neoplasm comprised of myeloid precursor cells.
It can occur in association with:
acute myeloid leukaemia (AML)
chronic myeloid leukaemia (CML)
other myeloproliferative disorders such as
myelofibrosis with myeloid meta...
Granuloma annulare is a benign idiopathic inflammatory disorder of the dermis, characterised by formation of dermal papules in young children.
Granuloma annulare has various clinical presentations:
three cutaneous forms
Granulomatosis with polyangiitis (GPA), previously known as Wegener granulomatosis, is a multisystem systemic necrotising non-caseating granulomatous vasculitis affecting small to medium sized arteries, capillaries and veins, with a predilection for the respiratory system and kidneys 3.
Breast involvement in granulomatosis with polyangiitis is seen in patients with avid systemic manifestations.
Clinically they can mimic carcinoma as a palpable, tender mass.
Granulomatosis with polyangiitis (or formerly known as Wegeners granulomatosis) is a ...
Ophthalmologic manifestations of granulomatosis with polyangiitis (GPA) (previously known as Wegener's granulomatosis), both ocular and orbital, have been reported in 40-50% of GPA patients 1-3 and can occur in either the classic or limited form of the disease. 4 Ophthalmologic disease occasiona...
This article discusses the pulmonary manifestations of granulomatosis with polyangiitis (previously known as Wegener's granulomatosis). It is classified as a type of pulmonary angiitis and granulomatosis.
For a general discussion of the condition, please refer to the main article on granulomato...
The renal manifestations of granulomatosis with polyangiitis (GPA) (previously known as Wegener's granulomatosis) are occult on imaging, especially when compared to the pulmonary changes. Approximately half of GPA patients have kidney disease at presentation. Granulomatosis with polyangiitis (We...
The upper respiratory tract manifestations of granulomatosis with polyangiitis (GPA) (previously known as Wegener's granulomatosis) are common and affect most patients. . Granulomatosis with polyangiitis (Wegener granulomatosis), is a multi-system systemic necrotizing non-caseating granulomatous...
Granulomatous invasive fungal sinusitis, sometimes termed granulomatous invasive fungal sinusitis, is a form of invasive fungal sinusitis. Reports describing the imaging findings have been uncommon 1.
It is rare and been mainly reported in Sudan, India, Pakistan and sometimes in t...
Granulomatous lung disease refers a broad group of infectious and well as non infections conditions characterised by formation of granulomas.
The spectrum includes
pulmonary non tuberculous mycobacterial infection
Granulomatous mastitis is a very rare breast inflammatory disease of unknown origin that can clinically mimic carcinoma of the breast.
The condition generally manifests as a distinct, firm to hard mass that may involve any part of the breast. The subareolar regions may be...