Allergic fungal sinusitis (AFS) is the most common form of fungal sinusitis, and is common in warm and humid climates. On imaging, it usually presents as opacification and expansion of multiple paranasal sinuses, unilaterally or bilaterally, with content that is centrally hyperdense on CT. MRI s...
Ameloblastic fibro-odontoma (AFO) is a rare benign mixed odontogenic tumour that usually arises in the maxilla and mandible. According to the 2005 WHO classification of odontogenic tumours, it is defined as a benign tumour that resembles ameloblastic fibroma but contains enamel and dentin.
Ameloblastomas are locally aggressive benign tumours that arise from the mandible, or, less commonly, from the maxilla. Usually present as a slowly but continuously growing hard painless lesion near the angle of the mandible in the 3rd to 5th decades of life, which can be severely disfiguring if...
Antrochoanal polyps (ACP) are solitary sinonasal polyps that arise within the maxillary sinus. They pass through and enlarge the sinus ostium and posterior nasal cavity to the nasopharynx.
Similar polyps can arise in the sphenoid sinus extending into the nasopharynx: these are termed sphenoch...
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...
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 lymphoepithelial lesions (BLL or BLEL), also misleadingly known as AIDS-related parotid cysts (ARPC), are mixed solid and cystic lesions that enlarge the parotid glands, and are usually associated with cervical lymph node enlargement, and nasopharyngeal lymphofollicular hyperplasia.
A Bezold abscess is a complication of acute otomastoiditis where the infection erodes through the cortex medial to the attachment of sternocleidomastoid , at the attachment site of the posterior belly of the digastric muscle, and extends into the infratemporal fossa. Due to it being deep to the ...
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...
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...
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.
Usually they are seen in the 4th to 6th decades. They are rare tumours.
Capillary haemangiomas of the orbit, also known as strawberry haemangiomas, on account of its colouring, or orbital infantile haemangiomas, are the most common orbital tumours of infancy, and unlike orbital cavernous haemangiomas, they are neoplasms rather than vascular malformations.
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...
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.
These tumours usually occur in older patients (6th to 8th decade), who have had a p...
Carcinosarcomas are highly malignant biphasic tumours with both carcinomatous (epithelial) and sarcomatous (bone, cartilage, or skeletal muscle) components.
It can arise in many organs:
lung 5: pulmonary carcinosarcoma
oesophagus 1: oesophageal carcinosarcoma
genitourinary tract ...
Caroticocavernous fistulas (CCF) represent abnormal communication between the carotid circulation and the cavernous sinus. They can be classified as direct or indirect which are separate conditions with different aetiologies.
Direct CCFs are often secondary to trauma, and as suc...
Carotid body tumour, also known as a chemodectoma or carotid body paraganglioma, is a highly vascular glomus tumour that arises from the paraganglion cells of the carotid body. It is located at the carotid bifurcation with characteristic splaying of the ICA and ECA.
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...
Cataract is an opacification or thickening of the lens and is the leading cause of blindness in the world 2.
Visual deterioration occurs with increasing degrees of severity. The diagnosis is made clinically.
Common causes include:
old age (most co...
Cavernous sinus thrombosis (CST) is a rare condition, most commonly infectious in nature, and the diagnosis on imaging is not always straightforward. It has high mortality and morbidity rates.
CST is rare with ~4.5 cases per 1,000,000 per year 5. It is the least common dural venou...
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.
In the 2005 WHO histological classification of odontogenic tumours, this tumour is referred to as "ossifyin...
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.
Cementoblastomas have been previously described in the literatur...
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...
Cherubism has historically been considered a variant of fibrous dysplasia, but in reality is likely a distinct entity.
Cherubism is inherited as an autosomal dominant 2 disorder of variable penetrance, with onset in early childhood (typically in the 3-4 years of age). Interesting...
Choanal atresia refers to a lack of formation of the choanal openings. It can be unilateral or bilateral.
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 ...
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.
The mass is lined by epithelium (facing inwards) which continues to grow, the...
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.
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
Choroidal detachment is a detachment of the choroid from the underlying sclera due to increased intraocular pressure (IOP), and occurs in some settings:
exudative: fluid accumulating in the suprachoroidal space secondary to many causes, most commonly inflammation (e.g. uve...
Chronic invasive fungal sinusitis (CIFS) is a form of invasive fungal sinusitis.
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....
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.
Chronic otomastoiditis with tympanosclerosis represents calcific or bony middle ear foci secondary to suppurative chronic otomastoiditis.
Common locations of calcifications include:
Chronic sinusitis refers to ongoing long term sinus infection-inflammation that often develops secondary to a prolonged/refractory acute sinus infection.
It most commonly affects young to middle-aged adults but can uncommonly affect children.
deviated nasal ...
Cirsoid aneurysms are rare arteriovenous malformations of the scalp and extremities.
Patients often present with a slow-growing pulsatile mass and may also experience bleeding, tinnitus and/or a headache 3.
Cirsoid aneurysms develop due to an abnormal arteri...
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.
The most common forms of Coccidioides spp are Coccidioides immitis and Coc...
Cochlear aplasia, or complete absence of the cochlea is a rare anomaly which accounts for only 3% of cochlear malformations.1
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...
Cochlear hypoplasia is defined by small underdeveloped cochlea <2 turns.
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
Colloid nodules are non-neoplastic benign nodules occurring within the thyroid gland. They form the vast majority of nodular thyroid disease.
Colloid nodules are composed of irregularly enlarged follicles containing abundant colloid. Some colloid nodules can be cystic (cystic colloid...
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.
confluence of the cochlea, vestibule and horizontal SCC in a cystic c...
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.
The commonest presentation is t...
Congenital cataracts are a major cause of blindness with early detection the most important factor in reducing impact on future vision.
Incidence is ~3 per 100,000 in the United Kingdom 1. Will be higher in areas with increased rates of congenital infection 5.
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.
Although the term...
Cricopharyngeal muscle spasm is also known as cricopharyngeal achalasia, although some authors distinguish between these entities, and may present as a cause of dysphagia.
There is confusing use of the terms cricopharyngeal muscle spasm, cricopharyngeal achalasia and cricopharyngea...
Cystic hygroma, also known as cystic lymphangioma, refers to the cystic variety of congenital lymphangioma which, most commonly, occur in the cervicofacial regions, particularly at the posterior cervical triangle.
They usually occur in the fetal/infantile and paediatric populati...
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.
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.
Dacryocystoceles, although rare, are the second mo...
De Quervain thyroiditis, or subacute granulomatous thyroiditis, is a form of self-limited subacute thyroiditis usually preceded by upper respiratory tract viral infection such as mumps, measles, coxsackie virus, adenovirus, and influenza viruses.
It usually affects middle age fema...
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.
It is one of the causes of pulsatile tinnitus and is a common cause of a ...
Dental caries are very common but can lead to serious morbidity.
Dental caries are areas of focal enamel and dentin deminerlisation. There are multiple theories in their pathogenesis but contributing factors include a combination of diet, anatomy, oral cavity microbiome and time 1,2...
Dentigerous cysts, also called follicular cysts, are slow growing benign and non-inflammatory odontogenic cysts that are thought to be developmental in origin.
On imaging, they usually present as a well-defined and unilocular radiolucency surrounding the crown of an unerupted or impacted tooth ...
The dermolipoma is one of the fat-containing epibulbar mass lesions of lateral canthal area beneath the temporal or superotemporal bulbar conjunctivae.
Dermolipomas are congenital and more commonly seen in young patients with mean age of 30 years old. There is no gender predilect...
Diabetes insipidus (DI) is the deficiency or resistance to the hormone vasopressin (antidiuretic hormone), which results in polyuria and polydipsia.
DI occurs in 3 per 100,000 people 2.
DI may be described as 1-3:
central/neurogenic/hypothalamic: vasopressin deficie...
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.
ED is rare with an estimated prevalence of 1:...
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.
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 ...
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.
External auditory canal atresia (EACA) is characterised by complete or incomplete bony atresia of the external auditory canal (EAC) and, especially when seen in the setting of an associated syndrome, a dysplastic auricle and abnormal middle ear cavity.
The incidence is 1 in 10,000...
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 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...
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 ...
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...
Fatty nodal metaplasia in the neck occurs as a result of chronic inflammation or radiotherapy 3. The normal fatty nodal hilum enlarges, such that the lymph node appears cystic. However, its center is of fatty density. There is no surrounding stranding, and the node otherwise looks normal.
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:
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).
The mechanism is different dependent on whether the underlying cause is hyper or hypothyroidism.
First branchial cleft cysts are a type of branchial cleft anomaly. They are uncommon and represent only ~7% of all branchial cleft cysts.
They are usually diagnosed in middle-aged women 3-4.
Their presentation can in the form of 3
asymptomatic - incidenta...
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.
They are uncommonly encountered, with a wide differential diagnosis - albeit that the underlying c...
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.
Follicular thyroid adenoma is more commonly f...
Globe ruptures are 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 m...
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 jugulare paraganglioma is a paraganglioma of the head and neck that is confined to the jugular fossa. While it is a rare tumour, it is the most common of the jugular fossa tumours.
The relative prevalence of glomus jugulare with respect to other head and neck paraganglioma ...
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 ...
Glomus vagale tumours are glomus tumours that occur along the path of the vagus nerve (CN X). They are a subset of extra-adrenal neuroendocrine tumours that are derived from the nonchromaffin paraganglion cells.
Typically presents as a painless mass behind the carotid ar...
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
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...
Ophthalmologic manifestations in granulomatosis with polyangiitis (GPA), 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 occasionally can be the initial clinical manifestation ...
The upper respiratory tract manifestations of granulomatosis with polyangiitis (GPA), which was formerly known as Wegener granulomatosis, are common and affect most patients.
The majority of patients of GPA have upper respiratory tract involvement, most commonly presenting with rh...
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...
Graves disease is an autoimmune thyroid disease and is the most common cause of thyrotoxicosis (up to 85%).
There a strong female predilection with the F:M ratio of at least 5:1. Typically presents in middle age.
Patients are thyrotoxic. Extra-thyroid manif...
Halitosis refers to the symptom of foul oral odour, commonly termed "bad breath", that patients can present with, usually to dental services.
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...
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.
Typically affects middle aged females (30-50 year age group with a F:M ratio of 10-15:1).
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...
Hypoparathyroidism results from reduced secretion of parathyroid hormone by the parathyroid glands. It results in hypocalcaemia.
tetany: peripheral paresthesia, carpopedal spasm, seizures
emotional lability, depression and anxiety, psychosis
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...
Hyrtl's fissure (also known as tympanomeningeal fissure) is a congenital infra-labyrinthic fissure. It is a very rare cause of spontaneous CSF ottorhoea.
this can be diagnosed on axial slices and coronal reformations
CT cisternography and radionuclide cisternography ...
Incisive canal cysts, also known as nasopalatine duct cysts (NPDC), are developmental, non-neoplastic cysts arising from degeneration of nasopalatine ducts. These ducts usually regress in fetal life. The persistence of ductal epithelium leads to formation of cyst.
It is considered the most comm...
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...
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.
It is important to note that it has been argued by some ...
Inverted papillomas are a type of Schneiderian papilloma. They are uncommon with distinctive pathological and imaging features.
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...
Jod-Basedow phenomenon is hyperthyroidism following iodine intake in a person with long term underlying thyroid disease.
Jod-Basedow phenomenon occurs due to either overactivation of the entire thyroid gland, or more commonly autonomous nodules within the gland after iodine repletion...