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.

176 results found
Article

Asteroid hyalosis

Asteroid hyalosis is a degenerative condition of the eye where there is accumulation of calcium soaps in vitreous chamber. Epidemiology 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...
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Behçet disease

Behçet disease is a multi-systemic and chronic inflammatory vasculitis of unknown aetiology. Epidemiology 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...
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Black eyebrow sign

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...
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Branchial cleft anomalies

Branchial cleft anomalies comprise of a spectrum of congenital defects that occur in the head and neck. Pathology 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...
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Calcifying epithelial odontogenic tumour

Calcifying epithelial odontogenic tumour, also known as a Pindborg tumour, is typically located in the premolar and molar region of the mandible, although up to a third are found in the maxilla. Epidemiology Usually they are seen in the 4th to 6th decades. They are rare tumours. Pathology As...
Article

Carcinoembryonic antigen

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...
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Carcinoma ex pleomorphic adenoma

Carcinoma ex pleomorphic adenoma is the most common of three malignant mixed tumours of salivary glands, and are thought to arise from pre-existing pleomorphic adenomas (or benign mixed tumours) 1. Epidemiology These tumours usually occur in older patients (6th to 8th decade), who have had a p...
Article

Carcinosarcoma

Carcinosarcomas are highly malignant biphasic tumours with both carcinomatous (epithelial) and sarcomatous (bone, cartilage, or skeletal muscle) components.  Pathology It can arise in many organs: lung 5: pulmonary carcinosarcoma oesophagus 1: oesophageal carcinosarcoma genitourinary tract ...
Article

Castleman disease

Castleman disease, also known as angiofollicular lymph node hyperplasia or giant lymph node hyperplasia, is an uncommon benign B-cell lymphoproliferative condition. It can affect several regions of the body although commonly described as a solitary mediastinal mass. There are two distinct subty...
Article

Cataract

Cataract is an opacification or thickening of the lens within the globe and is the leading cause of blindness in the world 2.  Clinical presentation Visual deterioration occurs with increasing degrees of severity. The diagnosis is made clinically. Pathology Aetiology Common causes include: ...
Article

Cementoblastoma

Cementoblastoma is one of many mandibular lesions is a rare tumour of the cementum, with only approximately 100 cases reported. Key to diagnosis both radiologically and histologically is attachment to the tooth root.  Terminology Cementoblastomas have been previously described in the literatur...
Article

Cemento-ossifying fibroma

Cemento-ossifying fibroma (COF) are rare, benign neoplasms that usually arise from the mandible or maxilla. They most often arise from the tooth bearing areas of these bones. Terminology In the 2005 WHO histological classification of odontogenic tumours, this tumour is referred to as "ossifyin...
Article

Charcot-Leyden crystals

Charcot-Leyden crystals consist of collections of bipyramidal crystalloid made up of eosinophilic membrane proteins, which occur in:  asthma 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...
Article

Cherubism

Cherubism has historically been considered a variant of fibrous dysplasia, but in reality is likely a distinct entity.  Epidemiology Cherubism is a rare disorder and the precise incidence is unknown. It is inherited in an autosomal dominant pattern 2 and has variable penetrance, with onset in ...
Article

Choanal atresia

Choanal atresia refers to a lack of formation of the choanal openings. It can be unilateral or bilateral. Epidemiology It frequently presents in neonates where it is one of the commonest causes of nasal obstruction in this age group. There is a recognised female predilection. The incidence is ...
Article

Cholesteatoma

Cholesteatoma is histologically equivalent to an epidermoid cyst and is composed of desquamated keratinizing stratified squamous epithelium forming a mass. They usually present with conductive hearing loss. Pathology The mass is lined by epithelium (facing inwards) which continues to grow, the...
Article

Chorioretinal lacunae

Chorioretinal lacunae refer to punched out lesions in pigmented layer of retina, usually around the optic disc. It is a considered a consistent feature of Aicardi syndrome.
Article

Choristoma

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. Examples include: adrenal choristoma (myelolipoma) nasopharyngeal choristoma facial nerve choristoma optic nerve...
Article

Choroidal detachment

Choroidal detachment is a detachment of the choroid from the underlying sclera due to increased intraocular pressure (IOP), and occurs in some settings: transudative: trauma exudative: fluid accumulating in the suprachoroidal space secondary to many causes, most commonly inflammation (e.g. uve...
Article

Chronic invasive fungal sinusitis

Chronic invasive fungal sinusitis (CIFS) is a form of invasive fungal sinusitis.  Clinical presentation The condition has a more prolonged course than acute invasive fungal sinusitis, usually more than 12 weeks 5. Patients are usually immunocompetent or have a milder level of immunocompromise....
Article

Chronic otomastoiditis with ossicular erosions

Chronic otomastoiditis with ossicular erosions (aka) non cholesteatomatous ossicular erosion or post inflammatory ossicular erosions is defined by the erosive changes involving the ossicles in the absence of cholesteatoma in patient with history of chronic otomastoiditis. Radiographic features ...
Article

Chronic otomastoiditis with tympanosclerosis

Chronic otomastoiditis with tympanosclerosis represents calcific or bony middle ear foci secondary to suppurative chronic otomastoiditis. Radiographic features Common locations of calcifications include: tympanic membrane ossicle surface stapes footplate muscle tendons ossicle ligaments ...
Article

Chronic sinusitis

Chronic sinusitis refers to ongoing long term sinus infection-inflammation that often develops secondary to a prolonged/refractory acute sinus infection. Epidemiology It most commonly affects young to middle-aged adults but can uncommonly affect children. Pathology Aetiology deviated nasal ...
Article

Cirsoid aneurysm

Cirsoid aneurysms are rare arteriovenous malformations of the scalp and extremities.  Clinical presentation Patients often present with a slow-growing pulsatile mass and may also experience bleeding, tinnitus and/or a headache 3.  Pathology Cirsoid aneurysms develop due to an abnormal arteri...
Article

Coccidioidomycosis

Coccidioidomycosis refers to an infection caused by the dimorphic fungus Coccidioides spp, usually localised to the lungs. This disease is not to be confused with the similarly named paracoccidioidomycosis. Epidemiology The most common forms of Coccidioides spp are Coccidioides immitis and Coc...
Article

Cochlear aplasia

Cochlear aplasia, or complete absence of the cochlea is a rare anomaly which accounts for only 3% of cochlear malformations.1 Radiographic features complete absence of the cochlea. Dense otic bone is seen at the anatomical site of the cochlea 2 cochlear nerve canal and cochlear nerve are abse...
Article

Cochlear hypoplasia

Cochlear hypoplasia is defined by small underdeveloped cochlea <2 turns. Radiographic features a small cochlear bud of variable length (usually 1–3 mm).  It has only one turn or a partial turn is seen cochlear nerve often hypoplastic or absent cochlear nerve canal: absent, narrow or normal ...
Article

Cochlear incomplete partition type I

Cochlear incomplete partition type I  (IP-I) is a type of cochlear anomaly associated with sensorineural hearing loss. Radiographic features CT The main findings on CT are: absent modiolus absent interscalar septum wide (most common) or normal cochlear nerve canal Absence of these structu...
Article

Cochlear incomplete partition type III

Cochlear incomplete partition type III (IP-III), also termed X-linked deafness, is a rare type of genetic cochlear anomaly associated with mixed conductive and sensorineural hearing loss.  Pathology It is caused a mutation in the POU3F4 gene located on the X chromosome. Clinical presentation ...
Article

Colloid nodule (thyroid)

Colloid nodules are non-neoplastic benign nodules occurring within the thyroid gland. They form the vast majority of nodular thyroid disease. Pathology Colloid nodules are composed of irregularly enlarged follicles containing abundant colloid. Some colloid nodules can be cystic (cystic colloid...
Article

Common cavity malformation

Common cavity malformation is defined by the absence of the normal differentiation between the cochlea and vestibule replaced by cystic structure. It accounts for about 25% of cochlear malformations 1.  Radiographic features confluence of the cochlea, vestibule and horizontal SCC in a cystic c...
Article

Common variable immunodeficiency

Common variable immunodeficiency (CVID) is a condition that is associated with an impaired immune system. It is considered the most common symptomatic primary immunodeficiency, and is characterised by recurrent respiratory tract infections. Clinical presentation The commonest presentation is t...
Article

Congenital cataract

Congenital cataracts are a major cause of blindness with early detection the most important factor in reducing impact on future vision.  Epidemiology Incidence is ~3 per 100,000 in the United Kingdom 1. Will be higher in areas with increased rates of congenital infection 5. Risk factors low ...
Article

Craniofacial fibrous dysplasia

Craniofacial fibrous dysplasia is one of four types of fibrous dysplasia and is characterised, as the name suggests, by involvement of the skull and facial bones. For a general discussion of the underlying pathology, refer to the parent article fibrous dysplasia. Terminology Although the term...
Article

Cricopharyngeal muscle spasm

Cricopharyngeal muscle spasm is also known as cricopharyngeal achalasia, although some authors distinguish between these entities, and may present as a cause of dysphagia. Terminology There is confusing use of the terms cricopharyngeal muscle spasm, cricopharyngeal achalasia and cricopharyngea...
Article

Cystic hygroma

Cystic hygroma, also known as cystic or nuchal lymphangioma, refers to the cystic variety of congenital lymphangioma which, most commonly, occur in the cervicofacial regions, particularly at the posterior cervical triangle.  Epidemiology  They usually occur in the fetal/infantile and paediatri...
Article

Dacryoadenitis

Dacryoadenitis is infection of the lacrimal gland results in diffuse homogeneous enlargement, which can sometimes compress the globe. Most common organisms are Staphylococcus aureus, mumps, infectious mononucleosis, and influenza virus.
Article

Dacryocystocele

Dacryocystoceles are caused by obstruction of both the proximal and distal ends of the nasolacrimal duct. An imperforate Hasner membrane causes the distal blockage, but the cause of proximal obstruction is less clearly understood. Epidemiology Dacryocystoceles, although rare, are the second mo...
Article

Dehiscent jugular bulb

Dehiscent jugular bulbs are present when the sigmoid plate between a high riding jugular bulb and the middle ear is absent, allowing the wall of the jugular bulb to bulge into the middle ear cavity. Epidemiology The estimated incidence may be around 3.5-7 % of the symptomatic population (e.g. ...
Article

Dental caries

Dental caries are cavities in teeth. They are very common and can lead to serious morbidity.  Pathology Focal enamel and dentin deminerlisation result in cavity formation. There are multiple theories in their pathogenesis but contributing factors include a combination of diet, anatomy, oral ca...
Article

De Quervain thyroiditis

De Quervain thyroiditis, or subacute granulomatous thyroiditis, is a form of self-limited subacute thyroiditis usually preceded by an upper respiratory tract viral infection such as mumps, measles, coxsackie virus, adenovirus, and influenza viruses. Epidemiology It usually affects middle age f...
Article

Dermolipoma

The dermolipoma is one of the fat-containing epibulbar mass lesions of lateral canthal area beneath the temporal or superotemporal bulbar conjunctivae. Epidemiology  Dermolipomas are congenital and more commonly seen in young patients with mean age of 30 years old. There is no gender predilect...
Article

Diabetes insipidus

Diabetes insipidus (DI) is the deficiency or resistance to the hormone vasopressin (antidiuretic hormone), which results in polyuria and polydipsia.  Epidemiology DI occurs in 3 per 100,000 people 2.  Pathology DI may be described as 1-3: central/neurogenic/hypothalamic: vasopressin deficie...
Article

Ectodermal dysplasia

Ectodermal dysplasia (ED) refers to a heterogeneous group of genetic disorders that cause abnormal ectoderm development. The effect is a non-progressive defect in the development of two or more tissues derived from embryonic ectoderm.  Epidemiology ED is rare with an estimated prevalence of 1:...
Article

Endolymphatic sac tumour

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.  Epi...
Article

Epiglottitis

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...
Article

Epignathus

Epignathus is a term given to a very rare form of teratoid tumour that arises from the oropharyngeal region. Epidemiology There may be a slight female predilection ref. The estimated incidence is ~ 1 in 35,000 to 200,000 births. Clinical presentation The tumour classically presents in utero ...
Article

Ethmocephaly

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.  Pathology Associations holoprosencephaly 1-2: particularly alobar holoprosencephaly See also cebocephaly
Article

Eustachian tube dysfunction

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. Epidemiology ETD is estimated to be present in ~1% of the adult population. Pathology...
Article

External auditory canal cholesteatoma

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.   Epidemiology The external acoustic cana...
Article

External auditory canal osteoma

External auditory canal osteoma is a rare focal pedunculated bony overgrowth of the osseous external auditory canal. Radiographic features solitary pedunculated bony overgrowth of the external auditory canal usually at the bony cartilaginous junction unilateral large lesions may be associate...
Article

Extracranial meningioma

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, ...
Article

Extramedullary plasmacytoma

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%. Epidemiology EMP occurs most commonly during the fourth through to seventh de...
Article

Exudative retinitis

Exudative retinitis (also known as retinal telangiectasis or Coats disease) is a rare congenital disease affecting the eyes and is a cause of leukocoria. Epidemiology The exact aetiology is unknown and the disease is a non hereditary disorder.  It occurs predominantly in young males, with the ...
Article

Factitious hyperthyroidism

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. Radiographic features Ultrasound The hypervascularity which is seen wi...
Article

Febrile infection-related epilepsy syndrome

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. Terminology FIRES has received several names in the literature: acute encep...
Article

Fetal goitre

A fetal goitre is an enlargement of the thyroid gland in utero. It can occur with either hyper or hypothyroidism (and in isolated cases of euthyroidism 8). Pathology The mechanism is different depending on whether the underlying cause is hyper or hypothyroidism.  Associations maternal Graves...
Article

First branchial cleft cyst

First branchial cleft cysts are a type of branchial cleft anomaly. They are uncommon and represent only ~7% of all branchial cleft cysts. Epidemiology They are usually diagnosed in middle-aged women 3-4.  Clinical presentation Their presentation can in the form of 3: asymptomatic, e.g. inci...
Article

Floating teeth

Floating teeth is the description given to the appearances on imaging of teeth 'hanging in the wind' as a result of alveolar bone destruction around the root of the teeth.  Differential diagnosis They are uncommonly encountered, with a wide differential diagnosis - albeit that the underlying c...
Article

Follicular thyroid adenoma

Follicular thyroid adenoma is a commonly found benign neoplasm of the thyroid consisting of differentiated follicular cells. It can not be differentiated from follicular carcinoma on cytologic, sonographic or clinical features alone 1. Epidemiology Follicular thyroid adenoma is more commonly f...
Article

Globe rupture

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...
Article

Globus pharyngeus

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...
Article

Glomus tympanicum paraganglioma

Glomus tympanicum paragangliomas (chemodectomas) are the most common middle ear tumour.  Epidemiology There is a female predominance (M:F = 1:3); presentation is most common when patients are more than 40 years old 1,2.  Clinical presentation May be incidental but symptomatic masses produce ...
Article

Goitre

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 neonate...
Article

Granulocytic sarcoma

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...
Article

Granulomatosis with polyangiitis (orbital manifestations)

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...
Article

Granulomatosis with polyangiitis (upper respiratory tract manifestations)

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...
Article

Granulomatous invasive fungal sinusitis

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. Epidemiology It is rare and been mainly reported in Sudan, India, Pakistan and sometimes in t...
Article

Graves disease

Graves disease is an autoimmune thyroid disease and is the most common cause of thyrotoxicosis (up to 85%). Epidemiology There a strong female predilection with the F:M ratio of at least 5:1. Typically presents in middle age. Clinical presentation Patients are thyrotoxic. Extra-thyroid manif...
Article

Halitosis

Halitosis refers to the symptom of foul oral odour, commonly termed "bad breath", that patients can present with, usually to dental services. Pathology It is thought to be caused by the presence of volatile sulphur compounds that are produced by bacteria. Although the underlying cause can be s...
Article

Hashimoto thyroiditis

Hashimoto thyroiditis, also known as lymphocytic thyroiditis or chronic autoimmune thyroiditis, is a subtype of autoimmune thyroiditis. It is one of the most common thyroid disorders.  Epidemiology Typically affects middle aged females (30-50 year age group with a F:M ratio of 10-15:1).  Clin...
Article

Head and neck squamous cell carcinomas

Head and neck squamous cell carcinomas (HNSCC) refer to SCCs of the aerodigestive tract of the head and neck rather than cutaneous SCCs. SCC is the most common tumour of the mucosa of the upper aerodigestive tract, and can occur anywhere there is squamous cell mucosa.  Epidemiology, risk factor...
Article

Hemifacial hypertrophy

Hemifacial hyperplasia or hemifacial hypertrophy is a rare developmental anomaly characterised by asymmetric growth of hard and soft tissues of the face 1. Epidemiology These asymmetries are often noted at birth and are usually accentuated with increasing age, especially around puberty 2. The...
Article

Hypoparathyroidism

Hypoparathyroidism results from reduced secretion of parathyroid hormone by the parathyroid glands. It results in hypocalcaemia.  Clinical presentation tetany: peripheral paresthesia, carpopedal spasm, seizures emotional lability, depression and anxiety, psychosis short stature Pathology T...
Article

Hypopharyngeal squamous cell carcinoma

Squamous cell carcinoma of the hypopharynx is relatively uncommon, carries the worst prognosis of any head and neck squamous cell carcinoma (HNSCC), and is a challenge to diagnose and treat.  Hypopharyngeal carcinoma is relatively uncommon representing only 10% of all proximal aerodigestive tra...
Article

Hyrtl’s fissure

Hyrtl's fissure (also known as tympanomeningeal fissure) is a congenital infra-labyrinthic fissure. It is a very rare cause of spontaneous CSF ottorhoea. Radiographic features CT this can be diagnosed on axial slices and coronal reformations CT cisternography and radionuclide cisternography ...
Article

Intracranial dermoid cyst

Intracranial dermoid cysts are uncommon lesions with characteristic imaging appearances. They can be thought of as along the spectrum: from epidermoid cysts at one end (containing only desquamated squamous epithelium) and teratomas at the other (containing essentially any kind of tissue from all...
Article

Intraosseous meningioma

Intraosseous meningioma, also referred as primary intraosseous meningioma, is a rare subtype of meningioma that accounts for less than 1% of all osseous tumours. They fall under the subgroup of primary extradural meningiomas. Terminology It is important to note that it has been argued by some ...
Article

Inverted papilloma

Inverted papillomas are a type of Schneiderian papilloma. They are uncommon with distinctive pathological and imaging features. Terminology  The term inverted papilloma is also used to describe a urothelial lesion. For a discussion of that entity, please refer to inverted papilloma of the urin...
Article

Jod-Basedow phenomenon (thyroid)

Jod-Basedow phenomenon is hyperthyroidism following iodine intake in a person with long term underlying thyroid disease. Pathology Jod-Basedow phenomenon occurs due to either overactivation of the entire thyroid gland or, more commonly, autonomous nodules within the gland after iodine repletio...
Article

Juvenile nasopharyngeal angiofibroma

Juvenile nasopharyngeal angiofibromas (JNA) are a rare benign but locally aggressive vascular tumour. Epidemiology Juvenile nasopharyngeal angiofibromas occur almost exclusively in males and usually in adolescence (~15 years). They account for only 0.5% of all head and neck tumours 2, but are ...
Article

Keratocystic odontic tumour

Keratocystic odontogenic tumours (KCOT or KOT), previously known as odontogenic keratocysts, are benign cystic neoplasms involving the mandible or maxilla and are believed to arise from dental lamina. They are locally aggressive and tend to recur after excision.  On imaging, they typically appe...
Article

Keratosis obturans

Keratosis obturans (KO) is a rare external auditory canal disease characterised by abnormal accumulation and consequently occlusion and expansion of the bony portion of the EAC by a plug of desquamated keratin. It can be confused by EAC cholesteatoma but they are completely different entities re...
Article

Labyrinthitis ossificans

Labyrinthitis ossificans (LO), also known as labyrinthine ossification, represents pathological ossification of the membranous labyrinth as a response to an insult to the inner ear. Clinical presentation It is usually associated with profound sensorineural hearing loss.  Pathology It most co...
Article

Laryngeal trauma

Laryngeal trauma is uncommon in the setting of external blunt or penetrating trauma. The larynx may also be injured internally, for example during endotracheal intubation. Clinical presentation Symptoms include hoarseness, laryngeal pain, dyspnoea, and/or dysphagia. Also, stridor, haemoptysis,...
Article

Laryngocoele

Laryngocoeles refer to dilatations of the laryngeal ventricular saccule located in paraglottic space of supraglottis. On imaging, these lesions are generally characterised as well-defined, thin-walled, fluid or air-filled cystic lesions in the paraglottic space. The communication with the laryn...
Article

Leiomyosarcoma

Leiomyosarcomas (LMS) are extremely rare malignant neoplasms that originate from smooth muscle cells and may be considered the malignant counterpart of a leiomyoma. They are classified as a soft tissue tumour and account for ~8% of malignant soft tissue tumours 10. Pathology Location  Leiomyo...
Article

Leptomeningeal cyst

Leptomeningeal cysts, also known as growing skull fractures, are an enlarging skull fracture that occurs near post-traumatic encephalomalacia. The term cyst is actually a misnomer, as it is not a cyst, but an extension of the encephalomalacia. Hence, it is usually seen a few months post-trauma. ...
Article

Ludwig angina

Ludwig angina refers to rapidly progressive inflammation (cellulitis) of the floor of mouth, which is potentially life threatening due to the risk of rapid airway compromise.  Epidemiology Largely due to the advent of antibiotics the condition is uncommon in present day modern societies. Immun...
Article

Mandibular osteoradionecrosis

Mandibular osteoradionecrosis (ORN) is more common after radiation therapy for head and neck malignancies due to the superficial position of the mandible, which exposes it to high radiation. The maxilla can also be involved, but this is less frequent.  Epidemiology Mandibular ORN may occur in ...
Article

Marjolin ulcer

Marjolin ulcers reflect malignant degeneration within pre-existing scars or areas of chronic inflammation such as burns, venous ulcers, etc.  
Article

Medial canal fibrosis

Medial canal fibrosis is characterised by fibrous tissue formation in the medial part of the bony external auditory canal. Clinical presentation  Patients can present with conductive hearing loss, otorrhea and/or a history of chronic otitis. Radiographic features Early stage thickened tympa...
Article

Medullary thyroid cancer

Medullary thyroid carcinoma (MTC) is a subtype of thyroid cancer which accounts for 5-10% of all thyroid malignancies. It occurs both sporadically (80%) and as a familial form. Epidemiology In nonfamilial cases it typically peaks in the 3rd to 4th decades. Pathology Thought to arise from par...

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