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 ...
Adenocarcinoma of the lacrimal glands is rare, with few cases reported in the literature since it was first described in 1996 1. Primary adenocarcinoma of the lacrimal gland is extremely rare; only 9 cases have been reported in the literature 1,2. It can be classified into high- and low-grade ma...
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
Alpha-thalassemia/mental retardation syndrome X-linked (ATRX) is an important genomic marker of gliomas. Loss/mutation of ATRX is almost never seen in patients with 1p/19q co-deletion (i.e. they are essentially mutually exclusive). Oligodendrogliomas will, therefore, have intact ATRX and 1p19q c...
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...
Anti N-methyl-D-aspartic acid (NMDA) receptor encephalitis is an autoimmune encephalitis with antibodies against the NMDA receptors. It is sometimes considered a form of autoimmune limbic encephalitis. It usually affects young patients particularly young females, in about 60% of whom ovarian ter...
Apocrine carcinoma of the breast is a rare variant of breast cancer. The diagnosis is mainly pathological as it is difficult to differentiate from other forms of breast cancer on imaging.
It accounts for about 4% of all cases. It is seen most often in females in the age group of 5...
Arachnoiditis is a broad term encompassing inflammation of the meninges and subarachnoid space.
Arachnoiditis affecting the cauda equina may be referred to as spinal/lumbar adhesive arachnoiditis.
Lumbar spine arachnoiditis can result in leg pain, sensory c...
Arteriosclerosis is defined by thickening and loss of elasticity of the arterial walls.
There are three patterns (arteriosclerosis is used as a generic term for all patterns above):
atherosclerosis: large and medium-sized arteries
Monckeberg medial calcific sclerosis: muscular arteries
An arteriovenous fistula (AVF) is an abnormal connection between an adjacent artery and vein. Unlike an arteriovenous malformation (AVM), these are frequently acquired lesions, rather than developmental abnormalities.
AVFs have a number of etiologies. They can be iatrogenic in origin...
Asbestosis refers to later development of diffuse interstitial fibrosis secondary to asbestos fibre inhalation and should not be confused with other asbestos related diseases.
Asbestosis typically occurs 10-15 years following the commencement of exposure to asbestos and is dose re...
Ascending aortic aneurysms are the most common subtype of thoracic aortic aneurysms, and may be true or false injuries.
Ascending aortic aneurysms represent 60% of thoracic aortic aneurysms.
Typically ascending aortic aneurysms are an incidental finding a...
Ascending transtentorial herniation is a situation where space occupying lesions in the posterior cranial fossa cause superior displacement of superior parts of the cerebellum through the tentorial notch.
nausea and/or vomiting
rapid progression toward decreased level ...
Ascites is defined as an abnormal amount of intraperitoneal fluid.
Patients with a large volume of ascites can present with abdominal distension (which may be painful), nausea, vomiting, dyspnoea and peripheral oedema 7, 9.
Ascitic fluid is traditionally chara...
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.
Asteroid hyalosis is a degenerative condition of the eye where there is accumulation of calcium soaps in vitreous chamber.
The prevalence increases with age from 0.2% 43-54 year olds to 2.9% in 75-86 year olds. The overall prevalence is 1.2%. It is more commonly unilateral and fav...
Asthma is a relatively common condition that is characterised by at least partially reversible inflammation of the airways and reversible airway obstruction due to airway hyper-reactivity. It can be acute, subacute or chronic.
Asthma is one of the most common chronic diseases in t...
Astroblastomas are rare glial tumours usually found in the cerebral hemispheres of young adults and children.
They occur at all ages range from early childhood to 6th decade but are most commonly seen in children, adolescents, and young adults with a mean age between 10-30 years ...
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 ...
Asymmetrical intrauterine growth restriction is a type of intrauterine growth restriction (IUGR) where some fetal biometric parameters are disproportionately lower than others, as well as falling under the 10th percentile. The parameter classically affected is the abdominal circumference (AC).
Atlanto-occipital dissociation (AOD) injuries are severe and include both atlanto-occipital dislocations and atlanto-occipital subluxations.
The tectorial membrane and alar ligaments provide the most stability to the atlanto-occipital joint, and injury to these ligaments results in i...
Atretic parietal cephalocoeles (APC) also known as atretic cephalocele, refers to small subscalp lesions that consist of dura, fibrous tissue, and dysplastic brain tissue.
Common presentation in infants and young children.
Palpable midline parietal soft ti...
Atrial-oesophageal fistulas are rare pathological connections between the left atrium and the oesophagus.
The presentation is non-specific. Patients may complain of fever, malaise, dysphagia or present with neurological symptoms 3.
The chief cause of atrial-...
Atrophic gastritis is a chronic condition of autoimmune and non-autoimmune aetiology.
Two types of atrophic gastritis have been described 1-3:
type A: autoimmune
gastric body and fundus atrophy secondary to antiparietal cell antibodies
decreased secretion of acid and intrinsic fa...
Atypical ductal hyperplasia (ADH) is a histologically borderline lesion that has some, but not all the features of ductal carcinoma in situ (DCIS). Sometimes the distinction between ADH and DCIS is simply on the basis of the number of ducts involved.
Atypical ductal hyperplasia is a...
Atypical lobular hyperplasia (ALH) is a pre-malignant lesion of the breast which falls at the milder end of the spectrum of lobular neoplasia. It is therefore considered a part of borderline breast disease.
It is usually asymptomatic and mammographically occult and is in...
Atypical meningioma refers to a more aggressive form of meningioma and denotes a WHO grade II tumour (along with two histological variants clear cell meningioma and chordoid meningioma). Atypical meningiomas account for 20-30% of all meningiomas 1,3.
It should be noted that epidemiology, clini...
Atypical pneumonia refers to the radiological pattern associated with patchy inflammatory changes, often confined to the pulmonary interstitium, most commonly associated with atypical bacterial aetiologies such as Mycoplasma pneumoniae, Chlamydophila pneumoniae and Legionella pneumophilia. Viral...
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 ...
Autoimmune encephalitis (also known as autoimmune limbic encephalitis) is an antibody-mediated autoimmune-mediated inflammation of the brain, typically involving the limbic system, although all parts of the brain can be involved.
Autoimmune encephalitis can be divided broadly into two groups, ...
Autoimmune hepatitis is a rare type of chronic hepatitis, currently classified as "type 1" or "type 2". It may eventually lead to cirrhosis. The role of imaging is primarily to exclude other diagnoses and evaluate for complications.
It may occur in children or adults, but most pat...
Autosomal dominant osteopetrosis is the less severe type of osteopetrosis and should be considered and compared with the other subtype: autosomal recessive osteopetrosis. The autosomal dominant (AD) type is less severe than its autosomal recessive (AR) mate. Hence, it is also given the name "ben...
Autosomal dominant polycystic kidney disease (ADPKD), also sometimes more vaguely referred to as "adult polycystic kidney disease", is as the name would suggest, a hereditary form of adult cystic renal disease.
Autosomal dominant polycystic kidney disease is one of the most commo...
Autosplenectomy denotes spontaneous infarction of the spleen with resulting hyposplenism.
Autosplenectomy is most frequently encountered in patients with homozygous sickle cell disease, although it has also been reported in pneumococcal septicaemia 1, and SLE 2. The demographics t...
Avascular necrosis of the hip is more common than other sites, presumably due to a combination of precarious blood supply and high loading when standing.
The most common presenting symptom is a pain in the region of affected hip, thigh, groin, and buttock. Although few p...
Azoospermia refers to complete absence of sperm in the semen. It accounts for 5-10% of male infertility 1.
It can be obstructive or non-obstructive, e.g. primary testicular failure. This differentiation is of utmost importance, as obstructive azoospermia can be corrected by surgical ...
Baker cysts, or popliteal cysts, are fluid-filled distended synovial-lined bursa arising in the popliteal fossa between the medial head of the gastrocnemius and the semimembranosus tendons via a communication with the knee joint. They are usually located at or below the joint line.
Balo concentric sclerosis (BCS) is a rare and severe monophasic demyelinating disease, considered a subtype of multiple sclerosis, appearing as a rounded lesion with alternating layers of hyper and hypoattenuation giving it a characteristic 'bullseye' or 'onion bulb' appearance 1,9.
BALT lymphoma is an abbreviated term for bronchus-associated lymphoid tissue lymphoma. These neoplasms fall under the broader umbrella of mucosa associated lymphoid tissue (MALT) lymphomas. It is sometimes considered a type of primary pulmonary lymphoma.
Up to half of pat...
Barrett oesophagus is a term for intestinal metaplasia of the oesophagus. It is considered the precursor lesion for oesophageal adenocarcinoma.
Barrett oesophagus is thought to have a prevalence of 3-15% in patients with reflux oesophagitis. Mean age at diagnosis is 55 years old 5...
Bartholin gland abscess is a complication that may result from an infected Bartholin gland cyst.
Abscesses are usually in a similar location to Bartholin gland cysts. Features of Bartholin gland abscess are otherwise similar to Bartholin gland cyst described in separate ...
Basal ganglia haemorrhage is a common form of intracerebral haemorrhage, and usually as a result of poorly controlled long-standing hypertension. The stigmata of chronic hypertensive encephalopathy are often present (see cerebral microhaemorrhages).
Other sites of hypertensive haemorrhages are ...
Basilar artery hypoplasia is a rare vascular anomaly of the basilar artery.
Basilar artery hypoplasia is usually accompanied by one or more fo the following:
persistent carotid-vertebrobasilar anastomoses
hypoplastic V4 segments of the vertebral arteries
Baxter neuropathy is a nerve entrapment syndrome resulting from the compression of the inferior calcaneal nerve (Baxter nerve).
The inferior calcaneal nerve is the first branch of the lateral plantar nerve which courses in a medial to lateral direction between the abductor hallucis muscle and t...
Behçet disease is a multi-systemic and chronic inflammatory vasculitis of unknown aetiology.
The mean age at which Behçet disease occurs is 20-30 years. The disease is most prevalent in the Mediterranean region, Middle East and East Asia. The highest incidence has been reported in...
Benign enlargement of the subarachnoid spaces in infancy (BESS or BESSI) also known as benign external hydrocephalus (BEH) is, as the name implies, a benign enlargement of subarachnoid spaces seen in infancy. It usually involves the frontal lobe subarachnoid spaces, and it is characterised clini...
Benign fibrous histiocytoma is closely related to fibroxanthoma of bone, is a rare lesion usually occurring in the skin where it is known as dermatofibroma.
Typically presents with pain, and most often in the third decade.
Only a few case reports have been pub...
Benign metastasising leiomyoma (BML) is a rare metastatic phenomenon that is observed when a pelvic leiomyoma is present.
Women who have undergone hysterectomy for leiomyomas are most commonly affected.
Patients are usually asymptomatic at presentation. A h...
Beta catenin mutated hepatic adenomas are a genetic and pathologic subtype of hepatic adenoma. Their appearance and prognosis are different than other subtypes.
They are the least common subtype of hepatic adenoma (10-15%). They occur more frequently in men and are associated with...
A biceps brachii rupture can occur at either superior or inferior end but most commonly involves the long head at its proximal attachment to superior glenoid labrum.
The biceps tendon has a fibrous covering (the lacertus fibrosus) that can clinically feel similar to an intact tendon even though...
Biceps chondromalacia is an attritional lesion of the humeral head caused by repeated abrasion by the intra-articular segment of the long head of biceps tendon.
The long head of biceps brachii arises from the supraglenoid tubercle of the glenoid fossa and has intrarticular and extra-...
Bicipitoradial bursitis refers to inflammation of the bicipitoradial bursa.
The bicipitoradial bursa surrounds the biceps tendon in supination. In pronation, the radial tuberosity rotates posteriorly, which compresses the bicipitoradial bursa between the biceps tendon and the radial cortex whi...
Bicuspid aortic valve (BAV) refers to a spectrum of deformed aortic valves with two functional leaflets or cusps which are often unequal in size.
They are most often congenital while an acquired bicuspid valve occurs when there is fibrous fusion between the right and left cusps of a pre-existin...
Bilateral hilar lymph node enlargement can arise from many causes, which include:
lymphoma: more common in hodgkin lymphoma than non-hodgkin lymphoma.
inorganic dust disease
Ascariasis is the commonest helminthic infection world wide and estimated to affect nearly 1 billion people (25% of population). The disease is transmitted by Ascaris lumbricoides which belongs to the nematode family (roundworms).
Infection occurs by ingestion of contaminated food (...
Bilomas refer to extrabiliary collections of bile. They can be either intra- or extrahepatic.
There is a slight discrepency in the reported literature in the use of the term "biloma". Many authors have used it exclusively to refer to intrahepatic bile collections or other bilious ...
Birth defects linked to antithyroid drug treatment in pregnancy have for a long time been known to exist. A recent Danish register-based cohort study has assessed the degree of association of antithyroid drugs, such as methimazole (MMI) / carbimazole (CMZ) and propylthiouracil (PTU), and the spe...
Bisphosphonate-related proximal femoral fractures are an example of insufficiency fractures, although the direct causative link remains somewhat controversial 2.
The atypical fracture pattern occurs in the proximal third of the femur, typically subtrochanteric, and may be unilateral or bilatera...
Bizarre parosteal osteochondromatous proliferation (BPOP) (also known as a Nora lesion) is a benign exophytic osteochondral lesion which has an appearance similar to an osteochondroma, and is typically seen in the hands and feet.
BPOPs are continuous with the underlying cortex, but usually wit...
Black eyebrow sign is the description given on plain facial radiographs to intra-orbital air 1.
Air rises into the most superior aspect of the orbit, almost always in the context of a facial fracture, in a linear fashion, giving the appearance of a eyebrow. The fracture is usually an orbital bl...
Bladder and ureteric tuberculosis (TB) refers to infection of ureters and urinary bladder with M. tuberculosis.
characteristic beaded appearance due to alternate areas of strictures and dilatation (chronic state)
acute: ureteral wall thickening
Bladder exstrophy (also known as ectopia vesicae) refers to a herniation of the urinary bladder through an anterior abdominal wall defect. The severity of these defects is widely variable.
The estimated incidence of bladder exstrophy is 1:10,000-50,000 live births 4,6. There is a ...
Blood blister-like aneurysm is a broad based bulge at non-branch point of a vessel.
Middle-aged patients with subarachnoid haemorrhage.
Focal arterial wall defect covered with fibrous tissue.
shape: blood blister-like or half-domed shal...
Bloom syndrome is a rare autosomal recessive disorder characterized by short stature, brachydactyly, malar hypoplasia and facial telangiectesia, erythema and cafe au lait spots. Affected individuals have increased risk of developing malignancies.
There is extreme chromosomal fragilit...
Blount disease refers to a local disturbance of growth of the medial proximal tibial epiphysis that results in tibia vara. The condition is commonly bilateral.
There is no recognised inheritance pattern.
Clinically, the child often presents with leg bowin...
Blunt cerebrovascular injury (BCVI) is an uncommon but serious consequence of blunt trauma to the head and neck.
It is often part of multi-trauma with a significant series of blunt trauma CTA reporting an incidence of approximately 1% 3. A large systematic review and meta-analysis...
Boerhaave syndrome refers to an oesophageal rupture secondary to forceful vomiting and retching.
It tends to be more prevalent in males, with alcoholism a risk factor. The estimated incidence is ~ 1:6000.
They are often associated with the clinical triad of...
Bone (marrow) contusion (bone bruising or bone marrow oedema) is an osseous injury which may result from compression of bone structures.
Bone contusions represent microfractures with haemorrhage and can progress to osteochondritis dissecans 2. They typically appear within 48 hours of...
Conditions associated with bone deformity from softening includes:
bowing of long bones
biconcave vertebral bodies / codfish vertebra
Bone infarction is a term used to refer to osteonecrosis within the metaphysis or diaphysis of a bone. Necrosis is a type of cell death due to irreversible cell injury, which can be recognised microscopically by alterations in the cytoplasm (becomes eosinophilic) and in the nucleus (swelling, py...
Bony humeral avulsion of the glenohumeral ligament (BHAGL) lesion is just like its slightly shorter relative HAGL lesion, except as the name suggests a bony avulsion fracture is seen at humeral insertion of the inferior glenohumeral ligament.
It is often associated with a subscapularis tear, an...
A botryoid rhabdomyosarcoma is a type of embryonal rhabdomyosarcoma and accounts for 5-10% of all rhabdomyosarcomas 6.
It tends to occur in paediatric population, often between birth and 15 years of age 7.
Rhabdomyosarcomas generally have a nonspecific infiltrative ap...
Bowdler spurs refer to transverse long bone midshaft spurs or osteochondral projections associated with hypophosphatasia. They typically occur in the fibulae and less commonly in the forearms.
Bowel and mesenteric trauma can result from blunt force, penetrating and iatrogenic trauma.
The bowel and mesentery are injured in ~2.5% (range 0.3-5%) of blunt force abdominal trauma 1,3,5,8. However not surprisingly, bowel and mesenteric injuries are more frequent after penetrat...
Bowel obstructions are common and account for 20% of admissions with "surgical abdomens". Radiology is important in confirming the diagnosis and identifying the underlying cause.
Bowel obstructions are usually divided according to where the obstruction occurs, and since imaging appearances, und...
Brachial plexus injuries are a spectrum of upper limb neurological deficits secondary to partial or complete injury to the brachial plexus, which provides the nerve supply of upper limb muscles.
Trauma, usually by motor vehicle accidents, involves severe traction on the ...
Brachiocephalic trunk pseudoaneurysms are rare.
The brachiocephalic trunk is the second most common site of chest vascular injury. Pseudoaneurysms can measure up to 4-5 cm in length with a diameter of 1.2 cm.
Most common causes are traumatic or iatrogenic injuries.
Treatment and ...
Brachymetatarsia (a.k.a. congenital short metatarsus) is a rare condition that develops from early closure of the growth plate.
Females are almost exclusively affected 1.
It typically involves the fourth ray or, less frequently, more than one metatarsal bon...
Brain abscess is a potentially life threatening condition requiring rapid treatment, and prompt radiological identification. Fortunately, MRI is usually able to convincingly make the diagnosis, distinguishing abscesses from other ring enhancing lesions.
Demographics reflect at-ri...
Branchial cleft anomalies comprise of a spectrum of congenital defects that occur in the head and neck.
The anomalies result from branchial apparatus (six arches; five clefts), which are the embryologic precursors of the ear and the muscles, blood vessels, bones, cartilage, and mucos...
A breast abscess is a relatively rare but significant complication of mastitis that may occur during breastfeeding, particularly in primiparous women. The clinical context is a key to diagnosis as imaging appearances (particularly ultrasound) can mimic many other entities such as breast carcinom...
Amyloid deposition in the breast is predominantly of two forms
breast involvement in primary amyloidosis - commoner
in association with other conditions like multiple myeloma, plasmacytosis and rheumatoid arthritis and another in the localised form which is rarer.
Breast aneurysms are a rarely seen cause of a breast mass.
true aneurysm: occurs post trauma and is seen as a slowly enlarging pulsatile mass
false aneurysm / pseudoaneurysm: occurs in acute trauma, post percutaneous biopsy, due to spontaneous haemorrhage secondary to coagulo...
Breast cellulitis is an acute pyogenic inflammatory change involving the dermis and subcutaneous tissue. This can be secondary to any wound, surgery or radiation for breast carcinoma.
inflammatory changes such as oedema, swelling and redness of the involved breast
Breast cysts are a relatively common cause of a breast lump in perimenopausal women, and usually causing wage pain or discomfort and slightly tender on palpation. They are a benign (BIRADS II) entity.
Breast cysts are caused by blockage of the terminal acini with resultant dilatation...
Breast haematoma can result from preceding direct trauma, surgery, biopsy (rare) or contusion and can be easily misinterpreted as other lesions such has breast malignancy if the correct clinical context is not taken into account. They can rarely occur spontaneously, especially in those with coag...
Breast hamartoma (also known as a fibroadenolipoma) is a benign breast lesion.
They typically occur in women older than 35 years of age.
While it can present as a painless soft lump, it may also present as unilateral breast enlargement without a palpable l...
Breast implant ruptures are a recognised complication of a breast implant. It can be intracapsular, when confined by the surrounding fibrous capsule, or extracapsular, when silicone freely extravasates.
After implantation of a silicone or saline breast implant, a fibrous capsule (sc...
Breast lipomas are a benign breast lesion and is classified as a BIRADS II lesion.
Lipomas are mostly asymptomatic and coincidentally discovered on routine mammography. Patients may present with a painless palpable breast lump which is soft and mobile. In these cases the ...