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.

120 results found
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Abscess

Abscesses are focal confined collections of suppurative inflammatory material and can be thought of as having three components 1: a central core consisting of necrotic inflammatory cells and local tissue peripheral halo of viable neutrophils surrounded by a 'capsule' with dilated blood vessel...
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Adult cervical lymphadenopathy (differential)

Cervical lymphadenopathy in an adult can result from a vast number of conditions. They include: malignancy metastases  from head and neck tumors lymphoma other neoplastic lesions Castleman disease Kaposi sarcoma infection bacterial infection viral infection Epstein-Barr virus herpes ...
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AIDS-defining illness

AIDS-defining illnesses are conditions that in the setting of a HIV infection confirm the diagnosis of AIDS, and do not commonly occur in immunocompetent individuals 2. According to the CDC surveillance case definition 1, they are: Infectious bacterial infections: multiple or recurrent candid...
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Atlantodental interval

The atlantodental interval (ADI), as the name suggests, is the horizontal distance between the anterior arch of the atlas and the dens of the axis, used in the diagnosis of atlanto-occipital dissociation injuries and injuries of the atlas and axis. It is the distance (in mm) between the posteri...
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Autoimmune thyroiditis

Autoimmune thyroiditis (plural thyroiditides) (AIT) refers to a group of conditions where there is inflammation of the thyroid gland secondary to thyroid autoantibodies. Epidemiology They are the most common thyroid disease group in the pediatric population 5. Pathology Entities that fall un...
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Basion-axial interval

The basion-axial interval (BAI), as the name suggests, is the horizontal distance between the basion and the posterior cortex of the axis, used in the diagnosis of atlanto-occipital dissociation injuries. It is the distance (in mm) between the basion and the superior extension of the posterior ...
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Basion-dens interval

The basion-dens interval (BDI), as the name suggests, is the distance between the basion and the tip of the dens, used in the diagnosis of atlanto-occipital dissociation injuries. It is the distance from the most inferior portion of the basion to the closest point of the superior aspect of the ...
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Benign metastasizing tumors

There are a number of benign metastasizing tumors: benign metastasizing meningioma 1,2 benign metastasizing leiomyoma 3 primary adenoma of thyroid 4 giant cell tumor of bone 5
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Benign minor salivary gland pathology

Benign minor salivary gland pathology is a broad term that encompasses a number of relatively uncommon pathologies that affect the minor salivary glands of the head and neck: salivary retention cysts benign neoplasms pleomorphic adenoma
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Bilateral thinning of the parietal bones

Bilateral thinning of the parietal bones, also known as biparietal osteodystrophy, is an uncommon, slowly progressive acquired disease of middle-aged people with slight female predilection. It is typically an incidental finding.  Pathology The etiology is unknown but is thought to be an age-re...
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Bimastoid line

The bimastoid line has been described and used to evaluate basilar invagination on frontal skull plain film and coronal reconstructed CT image. The bimastoid line is drawn between the inferior tips of the of mastoid processes bilaterally. The tip of the odontoid process of C2 normally projects ...
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Blunt traumatic neck injury

Blunt traumatic neck injury is uncommon because it is usually protected by the head, shoulders, and chest. This term is generally used to refer to injuries of the neck besides to cervical spine injuries, which are common.  Pathology Blunt injury to the neck is most commonly from motor vehicle ...
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Boogard's angle

Boogard's angle is measured by drawing a line from basion to opisthion and another line along the plane of the clivus to the basion intersecting the first line - the angle between these two lines is measured . The normal angle is 126° +/- 6°. If the angle measures more than 136° it is indicativ...
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Calcification of the external ear (differential)

Calcification of the external ear (auricular cartilage) may arise from a number of causes, including: hyperparathyroidism gout and pseudogout relapsing polychondritis frostbite trauma ochronosis sarcoidosis diabetes mellitus adrenal insufficiency
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Calcification of the globe (differential)

Calcification of the globe has many causes, varying from the benign to malignant. When calcification is seen of the posterior half of the globe, it could relate to any of the layers (scleral, choroidal or retinal), as it is not possible to separate them out on CT. Retinal drusen: 1% population...
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CEA

Serum CEA (carcinoembryonic antigen) is a cell-adhesive glycoprotein that was discovered in colorectal cancer in 1965, and is hence one of the oldest and most used tumor markers. Its name derives from its normal expression in fetoembryonic liver, gut and pancreas tissue. Normal range of CEA is ...
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Chamberlain line

Chamberlain line is a line joining the back of hard palate with the opisthion on a lateral view of the craniocervical junction. Significance It helps to recognize basilar invagination which is said to be present if the tip of the dens is >3 mm above this line. McGregor developed a modificatio...
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Cleft palate

Cleft palate is a type of facial cleft. It can occur in two main etiologically different forms: in association with a cleft lip: cleft lip +/- palate (much commoner) on its own: isolated cleft palate (rarer)
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Clival masses

The differential of a mass involving or arising from the clivus is a relatively narrow one and can be divided into whether the lesion arises from the skull base itself, the intracranial compartment above or the base of skull below. When evaluating the clivus it is important to compare the marro...
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Cochlear implant

Cochlear implants (CI) are a surgically implanted electronic device that provides a sense of sound to a person who is profoundly deaf or severely hard of hearing. Unlike conventional hearing aids, the cochlear implant does not amplify sound, but works by directly stimulating any functioning audi...
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COL4A1-related disorders

COL4A1-related disorders are a group of autosomal dominant disorders caused by a mutation in the COL4A1 gene. Epidemiology The exact prevalence is unknown, but the group of disorders is considered to be under-recognized, especially asymptomatic variants 1. Clinical presentation The clinical ...
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Conductive hearing loss

Conductive hearing loss is a hearing loss where the ears ability to conduct sound into the inner ear is blocked or reduced. It can be caused by a range of developmental, congenital or acquired pathology to the external, middle or inner ear. Pathology Essentially any process that obstructs or d...
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Congenital calvarial defects

Congenital calvarial defects are a group of disorders characterized by congenital calvarial bone defects that vary in severity. Radiographic features CT with 3D shaded surface reformats is the best imaging tool as it demonstrates calvarial defects and bone margins: parietal foramina parietal...
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Craniotomy

A craniotomy is a surgical procedure where a piece of calvarial bone is removed to allow intracranial exposure. The bone flap is replaced at the end of the procedure, usually secured with microplates and screws. If the bone flap is not replaced it is either a craniectomy (bone removed) or cranio...
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CSF otorrhea

CSF otorrhea is defined as leakage of cerebrospinal fluid (CSF) from the subarachnoid space into the middle ear cavity or mastoid air cells (cf. CSF rhinorrhea) Epidemiology There are a number of underlying causes, and thus no specific demographic is affected.  Clinical presentation Patients...
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Cystic mass adjacent to the angle of mandible (differential)

The differential diagnosis of a cystic mass adjacent to the angle of mandible includes: 2nd branchial cleft cyst lymphatic malformation (lymphangioma) cystic lymphadenopathy from tuberculosis from metastatic squamous cell carcinoma  from metastatic papillary thyroid cancer See also cys...
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Cystic (necrotic) lymph nodes

Cystic or necrotic appearing lymph nodes can be caused by a number of infectious, inflammatory or malignant conditions: Systemic squamous cell carcinoma metastases treated lymphoma leukemia plasmacytoid T-cell leukemia acute myeloid leukemia viral lymphadenitis herpes simplex lymphadenit...
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Cystic parotid lesions

The differential for cystic parotid lesions includes: bilateral cystic parotid lesions Warthin tumor benign lymphoepithelial lesions of HIV Sjögren syndrome sialocoeles unilateral cystic parotid lesion(s) Warthin tumor sialocoele first branchial cleft cyst parotid lymphangioma benign ...
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Dental abscess

Dental (periapical) abscess is an acute infection of the periapical tissue around the root of the tooth. Clinical presentation Patients may present with pain, edema, and purulent discharge localized to the site of pathology with or without fever and tender cervical lymphadenopathy 1. Patholog...
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Differential diagnosis for calcified masses in the mandible

Differential diagnosis for calcified masses in the mandible includes: calcifying odontogenic cyst (Gorlin cyst) calcifying epithelial odontogenic tumor (Pindborg tumor) fibrous dysplasia foreign body odontoma cemento-ossifying fibroma osteoma synovial osteochondromatosis focal sclerosi...
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Dysphagia

Dysphagia refers to subjective awareness of difficulty or obstruction during swallowing. It is a relatively common and increasingly prevalent clinical problem. Odynophagia is the medical term for painful swallowing. Fluoroscopy is the mainstay of imaging assessment but manometry can help evalua...
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Ectopia lentis

Ectopia lentis refers to subluxation or dislocation of the lens of the eye secondary to dysfunction or disruption of zonular fibers.  Pathology Etiology trauma systemic and syndromic disorders Marfan syndrome typically upwards and out most common spontaneous cause 2 homocystinuria -  typ...
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Endophthalmitis

Endophthalmitis is a potentially sight-threatening condition that involves intraocular inflammation of any cause. It is distinguished from panopthalmitis in that is does not extend beyond the sclera. It is either infectious or noninfectious in etiology, but in clinical practice, intraocular infe...
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Enlarged extraocular muscles (differential)

There is a short list of causes for enlarged extraocular muscles: thyroid associated orbitopathy lymphoma orbital pseudotumor sarcoidosis metastases amyloidosis (very rare) 2
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Epiphora

Epiphora represents excessive tearing of the eye and is a common clinical presentation to ophthalmological practice. It is most frequently due to an obstruction of the nasolacrimal drainage apparatus. Less commonly, overproduction of tears may be responsible. 
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Extraconal orbital lesions

Extraconal orbital lesions include lesions which arise from structures within the extraconal orbital space and those extending from adjacent structures into the orbits. Differential diagnosis Intraorbital lesions dermoid cyst: most common lesion in pediatrics  lacrimial gland lesions dacryo...
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Facial fractures

Facial fractures are commonly caused by blunt or penetrating trauma at moderate or high levels of force. Such injuries may be sustained during a fall, physical assault, motor vehicle collision, or gunshot wound. The facial bones are thin and relatively fragile making them susceptible to injury. ...
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Facial palsy

Facial palsy refers to the neurological syndrome of facial paralysis. It can result from a broad range of physiological insults to the facial nerve or its central nervous system origins. The most common causes of this is Bell palsy.  Terminology While facial palsy refers to the clinical presen...
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Focal calvarial thinning

Focal calvarial thinning can result from a number of causes. They include: bilateral thinning of the parietal bones (normal variant) most common arachnoid cyst mega cisterna magna peripherally located tumors (e.g. oligodendroglioma) See also calvarial thinning calvarial thickening
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Frontal bossing

Frontal bossing is a calvarial radiographic feature where the front of the skull appears protruding anteriorly. It is best appreciated on a sagittal or lateral image. Pathology This feature can be seen in many conditions (in alphabetical order): 18q syndrome acromegaly achondroplasia ß-tha...
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Heterogeneous thyroid echotexture

Heterogeneous echogenicity of the thyroid gland is a non-specific finding and is associated with conditions diffusely affecting the thyroid gland. These include: Hashimoto thyroiditis Graves disease
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Hiccups

Hiccups (or hiccoughs), medical term singultus (rarely used), are an unpleasant phenomenon, experienced by everyone on occasion, and usually self-limiting. However the much rarer intractable chronic form can be extremely debilitating. Epidemiology Hiccups are a symptom that has probably been e...
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High arched palate

High arched palates are a facial feature of many syndromes, although the classic association is Marfan syndrome. There are hundreds of conditions associated with high arched palates, with some of the radiologically-more important including: Down syndrome Apert syndrome Rubinstein-Taybi syndro...
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Hyperattenuating paranasal sinus opacification

Hyperattenuating paranasal sinus opacification can arise in a number of situations: fungal sinus disease inspissated secrections acute hemorrhage into sinus (hemosinus) Differential diagnosis In some situations can consider early calcification within the sinus - intrasinus calcification.
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Hyperostosis of the skull (differential)

Hyperostosis of the skull has many causes, broadly divided into focal or diffuse. Diffuse Paget's disease of bone metastatic disease, especially prostate carcinoma chronic, severe anemia hyperparathyroidism acromegaly osteopetrosis hyperostosis frontalis interna long-term phenytoin use ...
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Hypoglobus

Hypoglobus refers to the inferior displacement of the globe in the orbit. It may or may not be associated with enophthalmos. Hypoglobus is most commonly caused by fracture of the orbital floor but may be due to other causes: silent sinus syndrome orbital masses orbital foreign bodies thyroi...
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Hypotelorism

Hypotelorism refers to an abnormal decrease in distance between any two organs although some authors use the term synonymously with orbital hypotelorism meaning an abnormal decrease in the distance between the two eyes (the eyes appear too close together). The article mainly focuses on the latte...
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IgG4-related disease

IgG4-related disease (IgG4-RD) is a systemic disease that is characterized by extensive IgG4-positive plasma cells and T-lymphocyte infiltration of various organs. Terminology This condition has been known by many other names in the past, such as IgG4-related sclerosing disease, IgG4-related s...
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Ingested bones

Ingested bones that become lodged in the throat or gastrointestinal tract are a common presentation to the emergency department. Recognition is important because these cases can be potentially fatal.  Pathology Patients may present with a 'foreign body' feeling in the throat after eating fish ...
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Intraconal orbital lesions

Intraconal orbital lesions are broadly divided into two main groups; those with or without involvement of the optic nerves: Lesions with optic nerve involvement: optic nerve glioma optic nerve meningioma optic neuritis pseudotumor lymphoma and leukemia intracranial hypertension retinobla...
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Intrasinus calcification

Intrasinus calcification is a phenomenon whereby calcification is formed within the paranasal sinuses. It can occur to varying extents, therefore leading to varying degrees of attenuation on CT. Such calcification may occur either concurrently within an opacified sinus or in an aerated sinus, de...
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Jugular fossa masses

Jugular fossa masses comprise a range of pathological lesions that arise from or extend into the jugular fossa in the skull base. Although not a common location for tumors it is not unusual for jugular fossa lesions to be discovered incidentally on cross sectional imaging. Terminology Although...
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Lacrimal gland masses

Lacrimal gland masses​ can be classified into two broad groups - inflammatory (~50%) and neoplastic, either lymphoma (25%) or salivary gland type tumors (~25%).  Pathology Inflammatory sarcoidosis affects ~25% of patients with systemic disease orbital inflammatory pseudotumor lacrimal glan...
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Lacrimal sac mass

Lacrimal sac masses are very uncommon and more commonly have a malignant (~80%) rather than benign (~20%) etiology.  Pathology Etiology inflammatory granulomatosis with polyangiitis sarcoidosis orbital pseudotumor IgG4-related disease Sjogren syndrome neoplastic epithelial tumors beni...
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Laryngeal cyst

Laryngeal cysts can occur in any part of the larynx, but are more frequent in supraglottic locations, such as the epiglottis and vallecula. The prevalence of each location varies on different studies.  Epidemiology The laryngeal cysts represent a rare group, about 5%, of benign laryngeal lesio...
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Leukocoria

Leukocoria (also spelled as leucocoria or leukokoria) refers to an abnormal white reflection from the retina of the eye. Despite its color, the reflection is related to the familiar red-eye effect. Usually, when a light is shone through the iris, the retina appears red to the observer. In leukoc...
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Longitudinal temporal bone fractures

Longitudinal temporal bone fractures are petrous temporal bone fractures that occur parallel to the long axis of the petrous temporal bone. Although more current classifications of the extent of temporal bone fractures focus on the integrity of the otic capsule rather than the fracture orientati...
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Longitudinal versus transverse petrous temporal bone fracture

Petrous temporal bone fractures are classically divided into longitudinal, transverse or mixed fracture patterns depending on the direction of fracture plane with respect to the long axis of the petrous temporal bone. Some features may aid in distinguishing them.                 Longitudinal pe...
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Macrophthalmia

The increased globe size or macrophthalmia may have many differentials: buphthalmos (congenital glaucoma) axial myopia macrophthalmus in neurofibromatosis type 1 (NF1) connective tissue disorders: Marfan syndrome, Ehlers-Danlos syndrome Focal enlargement: staphyloma coloboma See also mi...
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Mandibular lesions

Mandibular lesions are myriad and common. The presence of teeth results in lesions that are specific to the mandible (and maxilla) and a useful classification that defines them as odontogenic or non-odontogenic. While it may often not be possible to make a diagnosis on imaging alone, this classi...
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Mandibular periostitis

There are many causes for mandibular periostitis: Langerhans cell histiocytosis malignancy (both primary and metastatic) necrosis, e.g. radiation osteonecrosis osteomyelitis pyogenic Garre's sclerosing osteomyelitis actinomycosis (uncommon) syphilis (uncommon) tuberculosis (uncommon) r...
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Mastoid air cell opacification

Mastoid air cell opacification can occur in a number of situations and can include a spectrum of inflammatory, neoplastic, vascular, fibro-osseous, and traumatic changes. They include otomastoiditis acute otomastoiditis chronic otomastoiditis radiation 3 trauma tumors primary tumors pla...
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McRae line

McRae line is a radiographic line drawn on a lateral skull radiograph or midsagittal section of CT or MRI, joining the basion and opisthion. Normal position of the tip of dens is 5mm below this line. If the tip of the dens migrates above this line it indicates the presence of basilar invaginati...
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Meckel cave lesions (differential)

Meckel cave lesions are numerous. The aim of this article is to list them in an easy way for revision and assessment of differential diagnosis.  Neoplastic Meckel cave tumors account for only 0.5% of all intracranial tumors. The most common histologies include: trigeminal schwannoma: most com...
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Medical devices in the neck

Medical devices in the neck are regularly observed by radiologists on plain film and CT reporting. They include devices which pass through the neck into the chest and stomach or ascend to/into the head. Vascular access devices dialysis catheters peripherally inserted central catheters (PICC) ...
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Middle ear tumors

There are a range of middle ear tumors, which are more likely to be benign than malignant.  Pathology The three most common middle ear tumors are (not in any particular order as there are differences in the literature) 1-3:  glomus tympanicum paraganglioma congenital cholesteatoma middle ea...
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Midline neck mass

Midline neck masses have a relatively narrow differential, as few structures are present in the midline. Dividing the causes according to structure of origin is a useful schema. lymph node(s): Delphian node(s) inflammatory adenopathy malignancy thyroid gland thyroglossal duct cyst thyroid ...
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Mucocele

A mucocele simply refers to accumulation and expansion of a structure by mucus. It occurs in a variety of locations which are discussed separately: paranasal sinus mucocele oral cavity e.g. ranula, mucous retention cysts mucocele of the appendix 1 mucocele of the gallbladder mucocele of the...
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Multiple cystic neck lesions (differential)

The differential diagnosis for multiple cystic neck lesions is different to that for a solitary cystic neck mass. Differential diagnosis Cystic neck lesions are seen in: necrotic metastatic SCC nodes: older patient, M>F papillary thyroid carcinoma metastases: usually a younger patient, F>M ...
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Multiple endocrine neoplasia syndromes

Multiple endocrine neoplasia (MEN) syndromes are a collection of syndromes characterized by the presence of, as the name would suggest, multiple endocrine tumors. They are autosomal dominant in inheritance. MEN1 (Wermer syndrome) MEN2 (multiple endocrine adenomatosis) MEN2a (Sipple syndrome) ...
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Obstruction of nasolacrimal drainage apparatus

Obstruction of nasolacrimal drainage apparatus results in epiphora and can be primary or secondary, congenital or acquired. Obstruction can occur at canalicular, lacrimal saccular, or nasolacrimal ductal (post-saccular) levels. Causes of obstruction Congenital obstruction persistence of the m...
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Ocular metastasis

Ocular metastases, also termed uveal metastases, account for over 80% of all ocular pathology, and need to be distinguished from extraocular metastasis, which are a quite different group of tumors. This article will discuss metastatic lesions affecting the orbits. For other intracranial metasta...
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Ocular pathology

Ocular pathology covers a wide range of conditions and therefore represents the cause of a wide range of symptoms, signs and radiographic features. Ocular metastases account for over 80% of all ocular pathology. With regard to the remainder of ocular lesions, the primary differentiating factor ...
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Odontohypophosphatasia

Odontohypophosphatasia is the mildest form of hypophosphatasia that manifests as tooth dysplasia and/or early loss of deciduous or permanent teeth. Pathology As with all forms of hypophosphatasia, the underlying abnormality is a mutation in the ALPL gene that encodes for tissue non-specific al...
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Ophthalmoplegia

Ophthalmoplegia describes the abnormal eye movement that occurs because of paralysis of one or more of the six extraocular muscles involved in eye movements. Classification can be based on the cause of the ophthalmoplegia or the directions of the affected movements. There are numerous causes of...
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Optic nerve enlargement

Enlargement of the optic nerves is uncommon and has a surprisingly broad differential: optic nerve glioma optic nerve meningioma orbital pseudotumor optic neuritis sarcoidosis leukemia orbital lymphoma metastases perioptic hemorrhage Erdheim-Chester disease juvenile xanthogranuloma m...
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Orbital cystic lesions

Several cystic and cyst-like orbital lesions may be encountered in imaging of the orbits: developmental orbital cysts choristoma dermoid: commonest benign orbital tumor in childhood  epidermoid teratoma  congenital cystic eye colobomatous cyst acquired abscess hematoma lacrimal gland ...
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Orbital inflammatory disease (differential)

The differential diagnosis of orbital inflammatory diseases (including orbital pseudotumors) can be divided based on their location into: dacryoadenitis of lacrimal glands myositis of extraocular muscles perineuritis of optic nerve orbital cellulitis preseptal postseptal orbital apicitis...
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Orbital mass

An orbital mass carries a relatively wide differential: tumors lymphoma metastasis lacrimal gland or duct tumors rhabdomyosarcoma of the orbit retinoblastoma optic nerve meningioma optic nerve glioma optic nerve schwannoma  neurofibroma developmental orbital cysts 3: choristoma epid...
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Orbital vascular lesions

Orbital vascular lesions may be difficult to distinguish on imaging. However, the following conditions have been described: arteriovenous malformation capillary hemangioma cavernous hemangioma lymphangioma / lymphangiovenous malformation / venolymphatic malformation orbital venous malformat...
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Otitis media

Otitis media refers to inflammation or infection of the middle ear cavity. Terminology The specific type of otitis media depends on various clinical findings and setting: acute otitis media: acute infection of the middle ear otitis media with effusion: middle ear fluid without signs or sympt...
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Oxalosis

Oxalosis results in supersaturation of calcium oxalate in the urine (hyperoxaluria), which in turn results in nephrolithiasis and cortical nephrocalcinosis.  This article focus on the secondary oxalosis, please refer to primary oxalosis for a specific discussion on this entity.  Pathology Cal...
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Pediatric cervical lesions (differential)

The differential diagnosis of pediatric cervical lesions is commonly encountered in practice, unfortunately, the list is long. Differential diagnosis Inflammatory Most lesions tend to be inflammatory 3: nontuberculous lymphadenitis scrofula sialodochitis abscess infected branchial cleft...
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Pediatric nasal cavity masses

Pediatric nasal cavity masses can occur within the nose or the nasopharynx. These masses are often found incidentally on imaging but can be readily apparent clinically. Clinical presentation The clinical features of these lesions tend to mimic upper respiratory processes and may result in dela...
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Parotid enlargement

Parotid enlargement (also known as parotidomegaly) has a wide differential given the significant breadth of pathology that can affect the parotid gland. These can be separated by the standard surgical sieve approach into infective, inflammatory, immune, neoplastic, infiltrative, and congenital c...
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Pedunculated intratracheal mass

A pedunculated intratracheal mass has a variety of differential diagnoses: benign tumor, e.g. hamartoma, chrondroma, lipoma hemangioma inspissated mucus metastasis to tracheal mucosa, e.g. renal cell carcinoma, melanoma polyp, e.g. inflammatory, antrochoanal papilloma post-intubation trac...
Article

Penetrating traumatic neck injury

Penetrating traumatic neck injury can be a potentially devastating injury due to the high density of crucial anatomical structures within the neck.  Epidemiology Young males are highly represented in patients with a traumatic neck injury. In one study, 11:1 ratio of males to females were ident...
Article

PET-CT indications

PET-CT is a combination of cross-sectional anatomic information provided by CT and the metabolic information provided by positron emission tomography (PET). PET is most commonly performed with 2-[F-18]fluoro-2-deoxy-D-glucose (FDG). Fluorine-18 (F-18) is an unstable radioisotope and has a half-...
Article

Petrous apex lesions (differential)

There is a wide differential diagnosis of petrous apex lesions: asymmetrical marrow / asymmetrical pneumatization non-expansile fat signal intensity on all sequences petrous apex cephalocoele 4 CSF signal intensity on all sequences petrous apicitis congenital cholesteatoma  restricted di...
Article

Phthisis bulbi

Phthisis bulbi, also known as end-stage eye, is an atrophic scarred and disorganized globe that may result from a variety of severe ocular insults.  Epidemiology In general, phthisis bulbi involves elderly patients, usually 65-85 years of age 7. Children and adolescents are only rarely affecte...
Article

Pneumoparotid

Pneumoparotid refers to air in the parotid gland and can cause unilateral/bilateral parotid swelling. In severe cases it can be associated with subcutaneous emphysema.  Pathology Any profession or recreation that increases oral positive pressure can cause air to reflux up the parotid ducts int...
Article

Powers ratio

The Powers ratio is a measurement of the relationship of the foramen magnum to the atlas, used in the diagnosis of atlanto-occipital dissociation injuries. The ratio, AB/CD, is measured as the ratio of the distance in the median (midsagittal) plane between the: basion (A) and the posterior spi...
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Primary malignancy of the nasopharynx

There are a number of primary malignancies of the nasopharynx: nasopharyngeal carcinoma (squamous cell carcinoma): 70% lymphoma (sinonasal lymphoma): 20% other nasopharyngeal papillary adenocarcinoma adenoid cystic carcinoma mucosal melanoma extramedullary plasmacytoma carcinosarcoma fi...

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