Ectopia cordis is an extremely rare congenital malformation where the heart is located partially or totally outside the thoracic cavity. The four main ectopic positions are::
adjacent to the thorax: ~60 %
The estimated ...
Ectopic pregnancy refers to the implantation of a fertilised ovum outside of the uterine cavity.
The overall incidence has increased over the last few decades and is currently thought to affect 1-2% of pregnancies. The risk is as high as 18% for first trimester pregnancies with bl...
Ectrodactyly (also known as a split hand-split foot malformation, cleft hand or lobster claw hand) is a skeletal anomaly predominantly affecting the hands (although the feet can also be affected). The condition has a highly variable severity.
The estimated incidence is at ~ 1 in 9...
Elastofibroma dorsi is a benign soft-tissue tumour with a characteristic location and imaging appearance.
It is more frequently seen in older women, with a reported female predilection of 5-13:1. The estimated mean age at diagnosis around 65-70 years.
Embryonal tumours with multilayered rosettes (ETMR) are rare small round blue cell tumour of the central nervous system and are one of the most aggressive brain tumours usually encountered in children.
Previously embryonal tumours with multilayered rosettes (ETMR) where known as e...
Emphysematous cholecystitis is a rare form of acute cholecystitis where gallbladder wall necrosis causes gas formation in the lumen or wall. It is a surgical emergency, due to the high mortality from gallbladder gangrene and perforation.
Men are affected twice as commonly as women...
Emphysematous cystitis (EC) refers to gas forming infection of the bladder wall.
The condition is rare and usually confined to certain patient subgroups.
Risk factors include:
considered the commonest predisposing factor 6
may be present in ~50%...
Emphysematous pancreatitis is an unusual complication of acute pancreatitis caused by necrotising infection of the pancreas. It is associated with gas-forming bacteria and characterized by the presence of gas within or around the pancreas.
Infection with gas-forming bacteria such as...
Emphysematous pyelonephritis refers to a morbid infection of kidneys, with characteristic gas formation within or around the kidneys. If not treated early, it may lead to fulminant sepsis and carries a high mortality.
The patient usually presents with flank pain, urinary...
Empyema necessitans (also sometimes spelt as empyema necessitasis) refers to extension of a pleural infection out of the thorax and into the neighbouring chest wall and surrounding soft tissues, e.g. extension of an empyema outwith the pleural cavity.
It may either occur due the viru...
Encephalitis lethargica (EL) is a rare disease that is also known as von Economo encephalitis. It affects the midbrain and basal ganglia, and the exact aetiology is unknown.
Symptoms are initially that of pharyngitis followed by lethargy, extrapyramidal movements (parkin...
Encephalocoele, also known as meningoencephalocele, is a form of neural tube defect and a type of cephalocoele where brain tissue and overlying meninges herniate out through a defect in the cranium.
It should be distinguished from cranial meningocele in which the lesion contains o...
Encephalomalacia is term given to describe softening or loss of brain parenchyma with or without surrounding gliosis, as a late manifestation of injury.
serve as a focus of seizure
Encephalomalacia is the end result of liquefactive necrosis of ...
Enchondromas (or chondromas 7) are a relatively common benign medullary cartilaginous neoplasm with benign imaging features. They account for the E in the popular mnemonic for bubbly bone lesions FEGNOMASHIC. They are sometimes classified under the umbrella term low grade chondral series tumours...
Endocardial fibroelastosis (EFE) is a rare cardiac condition which is classically described in the paediatric population (typically first two years). It is one of the causes for infants to present with unexplained heart failure.
The condition results from increasing amounts of fibro...
Endocrine tumours of the pancreas arise from the pancreatic islet cells and include some distinct tumours that match the cell type of origin.
Pancreatic endocrine tumours have commonly been referred to as "islet cell tumours", referring to the islets of Langerhans, from which they...
Endogenous lipoid pneumonia, also known as idiopathic lipoid pneumonia, is of the of the two types of lipoid pneumonias. It is also sometimes known as “cholesterol pneumonia” or “golden pneumonia”
Please refer to the main article for a broad discussion, including clinical presentation, radiogra...
Endolymphatic sac tumours (ELST) are very rare, locally invasive tumours of endolymphatic sac. Early detection of these tumours is critical, because early surgical intervention may prevent further hearing loss. Endolymphatic sac tumours do not metastasize but are highly locally aggressive.
Endometrial atrophy is a response to a hypo-oestrogenic state. If it occurs after menopause it can be more specifically termed postmenopausal endometrial atrophy.
While most patients are asymptomatic, endometrial atrophy is one of the commonest cause of postmenopausal bl...
Endometrial carcinoma is generally considered the most common gynaecological malignancy 1,5. It frequently presents with vaginal bleeding and both ultrasound and pelvic MRI are useful modalities for evaluation.
Incidence peaks at around the 6th decade, though 12% of cases present ...
Endometrial hyperplasia refers to an increased proliferation of the endometrial glands relative to the stroma. One of the main concerns is the potential malignant transformation of the endometrial hyperplasia to the endometrial carcinoma.
Endometrial hyperplasia affects women of a...
Endometrial stromal tumours (EST) are an uncommon group of tumours arising from endometrial stromal cells. It accounts for <2% of all uterine malignancies and 10% of all uterine sarcomas.
Half occur in premenopausal women, with most patients presenting in the 5th decade.
Endometrial thickness is a commonly measured parameter on routine gynaecological ultrasound and MR imaging. The appearance, as well as the thickness of the endometrium, will depend on whether the patient is of reproductive age or post-menopausal and, if of reproductive age, at what point in the ...
Endometrioid carcinoma of the endometrium is the most common histological subtype of endometrial carcinoma accounts for 85-90% of cases. It is considered a type I carcinoma of the uterus with slow progression and relatively good prognosis. Patients are usually 55 to 65 years old.
Endometrioid carcinomas of the ovary are a sub-type of epithelial ovarian tumours. The vast majority are malignant and invasive. On imaging, they are usually characterised as complex nonspecific solid-cystic masses and found associated with endometriosis.
Endometrioid carcinomas ...
Endometriomas, also known as chocolate cysts or endometriotic cysts, are a localised form of endometriosis and are usually within the ovary. They are readily diagnosed on ultrasound, with most demonstrating classical radiographic features.
These occur women of reproductive age.
Endometriosis affecting the canal of Nuck is an extremely rare site for endometriosis. It is proposed that retrograde implantation of endometrial tissue into patent canal of Nuck could give rise to the condition.
The condition is presented as a painful inguinal swelling. ...
Endometritis refers to inflammation or infection involving the endometrium. Endometritis can be acute or chronic and may arise in an obstetric setting, such as following delivery or miscarriage, or in a nonobstetric setting due to pelvic inflammatory disease (PID) or endometrial instrumentation....
An enostosis (pl. enostoses, also known as a "bone island") is a common benign bone lesion, usually seen as an incidental finding. They constitute a small focus of compact bone within cancellous bone. Enostoses can be seen on radiographs, CT, and MRI, and are considered one of the skeletal “don’...
En plaque meningiomas refer to a specific meningioma macroscopic appearance characterised by diffuse and extensive dural involvement, usually with extracranial extension into calvarium, orbit, and soft tissues. These tumours are thought to have a collar-like or sheet-like growth along the dura m...
An entero-enteric fistula is one formed between two parts of the small bowel.
The can result for a number of reasons most commonly with inflammatory bowel disease, in particular Crohn.
Enteropathic arthritis (EA) is a form of chronic, inflammatory arthritis associated with the occurrence of an inflammatory bowel disease (IBD), and is classified as a form of seronegative spondyloarthropathy.
Approximately 20% of people with Crohn disease or ulcerative colitis may...
Enterovirus rhomboencephalitis is the most common neurological complication of enterovirus infection 1.
Enterovirus rhomboencephalitis causes acute and severe neurologic disorders such as ataxia, nystagmus, oculomotor palsies, or bulbar palsy. In some cases, neurologic af...
Eosinophilic fasciitis (EF), also known as Shulman syndrome, is an uncommon connective tissue disorder.
It can potentially present at age. There is a recognized female predilection 3-4.
Patients typically present with pronounced extremity oedema and skin in...
Eosinophilic gastroenteritis (EG) is an uncommon disease characterised by diffuse infiltration of any or all layers of gut wall by eosinophils.
EG is an uncommon but not rare disease with slight male predominance, it can affect any age group but usually patients present in their...
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...
Epidermal inclusion cysts are common cutaneous lesions that represent proliferation of squamous epithelium within a confined space in the dermis or subdermis.
Synonyms include "epidermoid cyst" and "epidermoid inclusion cyst". These are occasionally termed "sebaceous cyst", althoug...
Epididymitis refers to inflammation of the epididymis, and may be associated with inflammation extending to the testis itself, in which case the term epididymo-orchitis is used. This should be distinguished from isolated orchitis, which is by comparison much less common.
Epidural angiolipomas are rare benign tumours composed of mature adipocytes and abnormal vessels.
Epidural angiolipomas are more frequently encountered in women, and typically in middle age (40-50 years of age) 1.
In keeping with the slow growth of these ...
Epiglottitis is a life-threatening condition caused by inflammation of the epiglottis and aryepiglottic folds 1, which can lead to acute airway obstruction. Hence, treatment should be urgent and performed by appropriately trained individuals, e.g. instrumentation of the trachea should be perfor...
Epignathus is a term given to a very rare form of teratoid tumour that arises from the oropharyngeal region.
There may be a slight female predilection ref. The estimated incidence is ~ 1 in 35,000 to 200,000 births.
The tumour classically presents in utero ...
Epipericardial fat necrosis is a rare self-limiting cause of an acute chest pain in an otherwise healthy individuals. It occurs within the mediastinum outside the pericardium.
The patient presents with an acute chest pain that may mimic other cardiopulmonary causes. It is...
Epiphrenic diverticula are pulsion diverticula of the distal oesophagus arising just above the lower oesophageal sphincter, more frequently on the right posterolateral wall.
They are less frequent than traction mid oesophageal diverticula, but may have more clinical relevance.
Epispadias is a rare congenital anomaly that is almost always associated with bladder exstrophy.
It occurs in 1 in 30,000 births, with a male: female ratio of 3:1.
In males, three types are described - glandular, penile and complete. Glandular form is most...
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).
Epithelial-myoepithelial carcinoma of lung is a very rare type of lung carcinomas of the salivary gland type.
Diagnosis is based on the identification of myoepithelial cells, with spindle cells, clear cells, or plasmacytoid differentiation or a mixture of phenotypes, along with a var...
Epithelioid glioblastoma is a variant of glioblastoma (along with gliosarcoma and giant cell glioblastoma) only recently added to the WHO classification of CNS tumours as part of the 2016 update 1.
Whether or not epithelioid glioblastomas are distinct from rhabdoid glioblastomas i...
Epithelioid haemangioendothelioma (EHE) is a rare relatively low grade vascular tumour. It occurs around medium to large venous structures.
It consists of rounded or slightly spindle-shaped eosinophilic endothelial (epitheloid) cells with rounded nuclei and prominent cytoplasmic vacu...
Erb palsy, also known as brachial plexus birth palsy, is a form of obstetric brachial plexus injury as a result of complications during delivery.
The most common cause is due to excessive lateral traction or stretching of the fetal head and neck in opposite directions du...
Erdheim-Chester disease (ECD) is a rare non-Langerhans cell, non-familial multisystemic granulomatosis, with widespread manifestations and of highly variable severity. The most common presenting symptom is bone pain.
Erdheim-Chester disease is a rare, non-inherited disease of midd...
Pulmonary manifestations of Erdheim-Chester disease are uncommon.
The lungs are affected in ~25% (range 20-35%) of cases 5.
Described findings include 1
symmetric reticular interstitial opacities
smooth interlobular septal thickening and fiss...
Essential thrombocythaemia (ET) refers to an acquired myeloproliferative neoplastic state characterised by an expansion of the megakaryocytic lineage, leading to an isolated elevation of platelets. It falls under the group of myeloproliferative disorders. It increases the risk of both thrombosis...
Ethmocephaly refers to a rare type of midline cranio-facial anomaly that is characterised by the presence of extreme hypotelorism, arrhinia and a midline proboscis.
holoprosencephaly 1-2: particularly alobar holoprosencephaly
Eustachian tube dysfunction (ETD) is considered by many to be the underlying cause of chronic otomastoiditis, although both the exact pathogenesis and role of ETD in chronic middle ear infections is unclear.
ETD is estimated to be present in ~1% of the adult population.
Ewing sarcoma is the second most common highly malignant primary bone tumour of childhood after osteosarcoma, typically arising from medullary cavity with invasion of Haversian system. They usually present as moth-eaten destructive permeative lucent lesions in the shaft of long bones with large ...
Ewing sarcoma family of tumours (ESFT), also referred as Ewing sarcomas of the chest wall, are malignant tumours affecting children and young adults, originating either from the osseous structures or the soft tissues of the chest wall.
On imaging, they are usually characterised as a large extr...
Excessive lateral pressure syndrome (ELPS) is abnormal lateral tilt of the patella without lateral translation and considered one of the relatively common causes of anterior knee pain. It can affect both adolescents or adults. Patients usually present with insidious onset anterior knee pain agg...
Exencephaly is a lethal congenital fetal brain developmental anomaly (neural tube defect) considered to be a precursor to anencephaly in the acrania-exencephaly-anencephaly sequence.
It is characterised by calvarial absence and loss of fetal brain tissue to variable degrees and is co...
Exophytic hepatic mass or tumour is a lesion which predominantly lies outside the margins of liver but originates from within the liver.
Causes include 1:
focal nodular hyperplasia
Exostoses are defined as benign growths of bone extending outwards from the surface of a bone. It can occur in any bone and be triggered by a number of factors. There are a number of examples of exostoses that occur due to local irritant stimuli:
exostosis of the external audit...
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...
External auditory canal cholesteatomas are an uncommon locations for cholesteatomas, which are usually in the middle ear or petrous apex. When they occur lateral to the tympanic membrane, they are referred to as external auditory canal cholesteatomas.
The external acoustic cana...
External auditory canal osteoma is a rare focal pedunculated bony overgrowth of the osseous external auditory canal.
solitary pedunculated bony overgrowth of the external auditory canal usually at the bony cartilaginous junction
large lesions may be associate...
Extracranial meningiomas, also known as primary extradural meningiomas or ectopic meningioma, are a rare location-specific type of meningioma that arise outside the dural covering of the brain and spinal cord. They are essentially extracranial tumours, most often occurring in the head and neck, ...
Extramedullary hematopoiesis (EMH) is a physiologic compensatory event in many hematologic diseases. It occurs most commonly in the spleen, liver, and lymph nodes and less frequently in the lung, pleura, breast, thymus, small bowel, and central nervous system.1
EMH in the adrenal is uncommon,2...
Extramedullary plasmacytoma (EMP) is an uncommon plasma cell tumour that is composed of monoclonal plasma cells arranged in clusters or sheets. The rate of progression to multiple myeloma (MM) varies from 10% to 30%.
EMP occurs most commonly during the fourth through to seventh de...
Extramural vascular invasion (EMVI) is the direct invasion of a blood vessel (usually a vein) by tumour. In rectal cancer, this can occur on a macroscopic level and be detected on staging MRI. It is a significant prognostic factor, being a predictor of haematogenous spread.
Extrapleural haematomas are uncommon and usually seen in the context of rib fracture, subclavian venous catheter traumatic insertion, and blunt chest injury.
Extrapleural haematomas result from the accumulation of blood in the extrapleural space where the overlying extrapleural fat i...
Extrapontine myelinolysis (EPM) is one of the complications occurring secondary to rapid correction of hyponatraemia, and is, along with central pontine myelinolysis encompassed by the more recent term osmotic demyelination syndrome.
In the vast majority of cases it is associated with central p...
Extrapulmonary tuberculosis (TB) refers to the haematogenous spread of Mycobacterium tuberculosis.
Extrapulmonary tubercuosis can occur as a primary form of the disease, i.e. direct infection of an extrapulmonary organ without the presence of primary pulmonary tuberculosis or it can ...
Extraskeletal Ewing sarcoma (EES) is included in the Ewing sarcoma family of tumors (ESFT) along with Ewing sarcoma of bone, primitive neuroectodermal tumor (PNET), peripheral neuroepithelioma, and thoracopulmonary PNET (Askin tumour). When compared with Ewing sarcoma of bone, extraskeletal Ewin...
Extraskeletal osteosarcoma (ESOS) is a rare mesenchymal malignant tumour that occurs in the retroperitoneum and soft tissue of extremities without any attachment to bone.
ESOS in contrast to other subtypes of osteosarcoma occurs infrequently in individuals under 40 years of age, m...
Exudative retinitis (also known as retinal telangiectasis or Coats disease) is a rare congenital disease affecting the eyes and is a cause of leukocoria.
The exact aetiology is unknown and the disease is a non hereditary disorder. It occurs predominantly in young males, with the ...
Fabry disease is a multisystem disorder which results from an X-linked inborn error of metabolism. The disease is characterised by a deficiency in hydrolase alpha-galactosidase activity with a resultant abnormal accumulation of globotriaosylceramide (Gb3) in various organ systems. In men, the co...
Facial nerve choristomas are rare, being characterised by non-neoplastic proliferation of smooth muscle cells and fibrous tissue. Facial nerve choristomas presumably can occur anywhere along the course of the facial nerve (CN VII), although the only cases reported are in the internal acoustic me...
Factitious hyperthyroidism or thyrotoxicosis factitia refers to precipitation of thyrotoxicosis due to exogenous ingestion of thyroid hormone (e.g. levothyroxine). It has been rarely associated with myocardial ischaemia 2.
The hypervascularity which is seen wi...
A faecaloma is a mass of faeces most frequently noted in the rectum and sigmoid colon, that is much harder than a faecal impaction due to coprostasis.
Usually, the faecal matter accumulates in the intestine, then stagnates and increases in volume until the intestine becomes deformed ...
In discussing mineralisation of the falx cerebri, many radiology textbooks use the term falx calcification and make no mention of falx ossification.
Ossification of dural folds is relatively unusual; one study suggested a prevalence of falx ossification of 0.7% 1. Even though, os...
Familial adenomatous polyposis syndrome (FAPS) is characterised by the presence of hundreds of adenomatous polyps in the colon. It is the most common of the polyposis syndromes.
Familial polyposis coli, attenuated familial adenomatous polyposis and Gardner syndrome are all variants...
Familial multiple lipomatosis (FML) is a hereditary syndrome of multiple encapsulated lipomas which are found on the trunk and extremities, with relative sparing of the head and shoulders.
It is clinically distinct from the similarly named multiple symmetric lipomatosis with which it is freque...
Fanconi anaemia (FA) is a rare disorder characterised by progressive bone marrow failure, various congenital abnormalities, and predisposition to malignancies (often acute myeloid leukaemia). It is considered the commonest type of inherited marrow failure syndrome 7.
Fatal familial insomnia is an extremely rare autosomally inherited prion disease 1. Unlike other prion diseases, it does not exhibit spongiform changes. The main pathological findings are gliosis in the inferior olivary nuclei and thalami.
Fat embolism syndrome (FES) is a rare clinical condition caused by circulating fat emboli leading to a multisystemic dysfunction. The classical clinical triad consists of:
It occurs in ~2.5% (range 0.5-4%) of th...
Fat necrosis within the breast is a pathological process that occurs when there is saponification of local fat. It is a benign inflammatory process and is becoming increasingly common with the greater use of breast conserving surgery and mammoplasty procedures.
Most at risk are mi...
In fat-pad impingement syndromes the aetiologies are different for each knee fat pad.
In anterior suprapatellar fat pad impingment syndrome the cause is usually due to either a developmental cause related to the anatomy of the extensor mechanism, or may be related to abnormal mechanics. In this...
Febrile infection-related epilepsy syndrome (FIRES) is a severe postinfectious neurological disorder that presents with status epilepticus in a previously normal child (or less commonly adult) after a febrile illness.
FIRES has received several names in the literature:
Femoral artery pseudoaneurysms are usually iatrogenic as the femoral artery is the vessel of choice for most endovascular arterial interventions.
inadequate compression following endovascular intervention
improper arterial puncture tec...
Femoral hernias are a type of groin herniation and comprise of a protrusion of a peritoneal sac through the femoral ring into the femoral canal, posterior and inferior to the inguinal ligament. The sac may contain preperitoneal fat, omentum, small bowel, or other structures.
Femoro-acetabular impingement (FAI) refers to a clinical syndrome of painful, limited hip motion resulting from certain types of underlying morphological abnormalities in the femoral head/neck region and/or surrounding acetabulum. FAI can lead to early degenerative disease.
Fetal anaemia can result from many causes.
haemolytic disease of the newborn
fetomaternal ABO incompatibility
fetomaternal rhesus (Rh) incompatibility
fetal parvovirus B19 infection
homozygous alpha thalassaemia 7
Fetal ascites refers to the accumulation of free fluid in the fetal abdomen. It is often considered under the same spectrum of hydrops fetalis.
any condition that results in hydrops fetalis
additional causes include
bowel perforation (e.g. meconium peritoniti...