Cervical lymphadenopathy in an adult can result from a vast number of conditions. They include:
from head and neck tumors
other neoplastic lesions
Calcification of the external ear (auricular cartilage) may arise from a number of causes, including:
gout and pseudogout
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.
drusen: 1% population...
Calcific cervical lymphadenopathy is uncommon and has a limited differential diagnosis, including malignant and benign etiologies. The most frequent causes include 1:
malignancies (more common)
metastatic thyroid carcinoma (most common; papillary or medullary types) 2,5
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...
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.
Essentially any process that obstructs or ...
Congenital calvarial defects are a group of disorders characterized by congenital calvarial bone defects that vary in severity.
CT with 3D shaded surface reformats is the best imaging tool as it demonstrates calvarial defects and bone margins:
The differential diagnosis of a cystic mass adjacent to the angle of mandible includes:
2nd branchial cleft cyst
lymphatic malformation (lymphangioma)
from metastatic squamous cell carcinoma
from metastatic papillary thyroid cancer
Cystic or necrotic appearing lymph nodes can be caused by a number of infectious, inflammatory or malignant conditions:
squamous cell carcinoma metastases
plasmacytoid T-cell leukemia
acute myeloid leukemia
herpes simplex lymphadenit...
The differential for cystic parotid lesions includes:
bilateral cystic parotid lesions
benign lymphoepithelial lesions of HIV
unilateral cystic parotid lesion(s)
first branchial cleft cyst
Differential diagnosis for calcified masses in the mandible includes:
calcifying odontogenic cyst (Gorlin cyst)
calcifying epithelial odontogenic tumor (Pindborg tumor)
Dysphagia refers to subjective awareness of difficulty or obstruction during swallowing. It is a relatively common and increasingly prevalent clinical problem. Odynophagia is the term for painful swallowing.
Fluoroscopy is the mainstay of imaging assessment but manometry can help evaluate the e...
Ectopia lentis refers to subluxation or dislocation of the lens of the eye secondary to dysfunction or disruption of zonular fibers.
systemic and syndromic disorders
typically upwards and out
most common spontaneous cause 2
homocystinuria - typ...
There is a short list of causes for enlarged extraocular muscles:
thyroid associated orbitopathy
amyloidosis (very rare) 2
Epiphora (plural: epiphoras) 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.
Extraconal orbital lesions include lesions which arise from structures within the extraconal orbital space and those extending from adjacent structures into the orbits.
dermoid cyst: most common lesion in pediatrics
lacrimial gland lesions
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.
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.
While facial palsy refers to the clinical presen...
Focal calvarial thinning can result from a number of causes. They include:
bilateral thinning of the parietal bones (normal variant) most common
mega cisterna magna
peripherally located tumors (e.g. oligodendroglioma)
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.
This feature can be seen in many conditions (in alphabetical order):
Heterogeneous echogenicity of the thyroid gland is a non-specific finding and is associated with conditions diffusely affecting the thyroid gland. These include:
Hyperattenuating paranasal sinus opacification can arise in a number of situations:
fungal sinus disease
acute hemorrhage into sinus (hemosinus)
In some situations can consider early calcification within the sinus - intrasinus calcification.
Hyperostosis of the skull has many causes, broadly divided into focal or diffuse.
Paget disease of bone
metastatic disease, especially prostate carcinoma
chronic, severe anemia
hyperostosis frontalis interna
long-term phenytoin use
Hypoglobus refers to the inferior displacement of the globe in the orbit. It may or may not be associated with enophthalmos.
fracture of the orbital floor (most common)
silent sinus syndrome
orbital foreign bodies
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...
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
lymphoma and leukemia
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...
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.
Lacrimal gland masses can be classified into two broad groups - inflammatory (~50%) and neoplastic, either lymphoma (25%) or salivary gland type tumors (~25%).
affects ~25% of patients with systemic disease
orbital inflammatory pseudotumor
Lacrimal sac masses are very uncommon and more commonly have a malignant (~80%) rather than benign (~20%) etiology.
granulomatosis with polyangiitis
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.
The increased globe size or macrophthalmia may have many differentials:
buphthalmos (congenital glaucoma)
macrophthalmus in neurofibromatosis type 1 (NF1)
connective tissue disorders: Marfan syndrome, Ehlers-Danlos syndrome
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...
There are many causes for mandibular periostitis:
Langerhans cell histiocytosis
malignancy (both primary and metastatic)
necrosis, e.g. radiation osteonecrosis
Garre's sclerosing osteomyelitis
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.
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.
Meckel cave tumors account for only 0.5% of all intracranial tumors. The most common histologies include:
trigeminal schwannoma: most com...
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
peripherally inserted central catheters (PICC)
There are a range of middle ear tumors, which are more likely to be benign than malignant.
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
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)
thyroglossal duct cyst
The differential diagnosis for multiple cystic neck lesions is different to that for a solitary cystic neck mass.
Cystic neck lesions are seen in:
metastatic squamous cell carcinoma: older patient, M>F
metastatic papillary thyroid carcinoma: usually a younger patient, ...
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)
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
persistence of the m...
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...
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 ...
Odontohypophosphatasia is the mildest form of hypophosphatasia that manifests as tooth dysplasia and/or early loss of deciduous or permanent teeth.
As with all forms of hypophosphatasia, the underlying abnormality is a mutation in the ALPL gene that encodes for tissue non-specific al...
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...
Enlargement of the optic nerves is uncommon and has a surprisingly broad differential:
optic nerve glioma
optic nerve meningioma
Several cystic and cyst-like orbital lesions may be encountered in imaging of the orbits:
developmental orbital cysts
dermoid: commonest benign orbital tumor in childhood
congenital cystic eye
lacrimal gland ...
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
An orbital mass carries a relatively wide differential:
lacrimal gland or duct tumors
rhabdomyosarcoma of the orbit
optic nerve meningioma
optic nerve glioma
optic nerve schwannoma
developmental orbital cysts 3:
Orbital vascular lesions may be difficult to distinguish on imaging. However, the following conditions have been described:
lymphangioma / lymphangiovenous malformation / venolymphatic malformation
orbital venous malformat...
Oxalosis is 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.
The differential diagnosis of pediatric cervical lesions is commonly encountered in practice, unfortunately, the list is long.
Most lesions tend to be inflammatory 3:
nontuberculous mycobacterial lymphadenitis
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.
The clinical features of these lesions tend to mimic upper respiratory processes and may result in dela...
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...
A pedunculated intratracheal mass has a variety of differential diagnoses:
benign tumor, e.g. hamartoma, chrondroma, lipoma
metastasis to tracheal mucosa, e.g. renal cell carcinoma, melanoma
polyp, e.g. inflammatory, antrochoanal
Penetrating traumatic neck injury can be a potentially devastating injury due to the high density of crucial anatomical structures within the neck.
Young males are highly represented in patients with a traumatic neck injury. In one study, 11:1 ratio of males to females were ident...
Periapical radiolucencies are commonly observed findings in OPG and other dental / head and neck imaging modalities.
They can represent a number of pathologies:
periapical lucency related to apical periodontitis
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-...
There is a wide differential diagnosis of petrous apex lesions:
asymmetrical marrow / asymmetrical pneumatization
fat signal intensity on all sequences
petrous apex cephalocoele 4
CSF signal intensity on all sequences
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.
In general, phthisis bulbi involves elderly patients, usually 65-85 years of age 7. Children and adolescents are only rarely affecte...
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.
Any profession or recreation that increases oral positive pressure can cause air to reflux up the parotid ducts int...
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...
There are a number of primary malignancies of the nasopharynx:
nasopharyngeal carcinoma (squamous cell carcinoma): 70%
lymphoma (sinonasal lymphoma): 20%
nasopharyngeal papillary adenocarcinoma
adenoid cystic carcinoma
Proptosis refers to forward protrusion of the globe with respect to the orbit. There are many causes of proptosis which can be divided according to location and it is worth remembering that it is not just orbital disease processes that cause proptosis.
Exophthalmos also describes f...
Pulsatile exophthalmos or pulsatile proptosis is a clinical symptom characterized by protrusion and pulsation of the eyeball that can occur due to various causes:
neurofibromatosis type 1 (with sphenoid wing dysplasia) 2
trauma (orbital r...
Pulsatile tinnitus is a specific type of tinnitus and refers to the perception of rhythmic noise, usually in time with the patient's heartbeat, in the absence of an external source, which is most commonly but not exclusively due to underlying vascular pathology.
Ranawat's line is the perpendicular distance between the center of the sclerotic ring of C2 and a line drawn along the axis of the C1 vertebra.
Normal value is 17 mm in males and 15 mm in females. It is decreased in basilar invagination.
History and etymology
Chitranjan S Ranawat is an Americ...
RASopathies are a class of developmental disorders caused by germline mutations in genes that encode for components or regulators of the Ras/mitogen-activated protein kinase (MAPK) pathway.
As a group, RASopathies represent one of the most common malformation syndromes, with an in...
Radiological manifestations of recreational drug use are not infrequently seen as the use of recreational drugs is widespread.
Interestingly, recent reports have suggested a decreasing incidence of reported drug use in the general population over the past decade, but it remains th...
Salivary gland tumors are variable in location, origin and malignant potential.
In general, the ratio of benign to malignant tumors is proportional to the gland size; i.e. the parotid gland tends to have benign neoplasms, the submandibular gland 50:50, and the sublingual glands and ...
Head and neck manifestations of sarcoidosis can have three main forms:
orbital involvement: orbital sarcoidosis
parotid gland involvement
nodal involvement: cervical lymphadenopathy in sarcoidosis
A scalp hematoma usually occurs following an injury at delivery although they are commonly seen with head trauma.
There are three types of hematoma, which are defined by their location within the scalp, particular their location as related to the galea aponeurosis and skull peri...
Sensorineural hearing loss (SNHL) refers to deafness secondary to conditions affecting the inner ear, internal acoustic canal, cerebellopontine angle, or vestibulocochlear nerve.
Conditions that cause SNHL can be divided by location:
otosclerosis (and othe...
Sincipital encephaloceles are congenital herniations of cerebral parenchyma through a cranial defect. There are three main types 1,2:
frontonasal encephalocele (~50%): more common in Asia and Latin America 4
naso-ethmoidal encephalocele (30%): more common in North America 4
The nasal passage and paranasal sinuses (collectively sinonasal) plays host to a number of diseases and conditions, which can be collectively termed sinonasal disease. One way of classifying separate entities is as follows:
inflammatory and infective conditions
The skull base angle allows the diagnosis of platybasia and basilar kyphosis. There are several different techniques that may be used on sagittal images from MRI or CT.
Traditionally, basal angle measurements were based on plain skull images. With the advent and generalization of MR imaging it ...
Skull tumors can be (as with tumors anywhere else) both primary and secondary, and benign or malignant.
giant cell tumor (GCT)
aneurysmal bone cyst (ABC)
epidermoid and dermoid cysts
Snake eyes, also known as snail eyes, is a term used to refer to the appearance of the facial nerve on coronal CT within its canal in the petrous temporal bone as the tympanic segment doubles back next to the labyrinthine segment. Anteriorly, these two segments converge at the geniculate ganglio...
Soft-tissue sarcomas are a heterogeneous group of malignant tumors of mesenchymal origin (sarcoma) that originate from the soft tissues rather than bone. They are classified on the basis of tissue seen on histology. The commoner sarcomas in the adult and pediatric population are listed below.
Telecanthus (rare plural: telecanthi) represents an increased intercanthal distance. It is often used interchangeably with hypertelorism, referring to increased distance between the eyes.
Causes and associations
trauma: naso-orbito-ethmoidal (NOE) fractures
Temporomandibular joint (TMJ) effusions are unusual in asymptomatic patients, and thus should trigger a careful search for underlying pathology. It usually precedes osteoarthritis of the TMJ. Effusions are seen in:
rheumatoid arthritis (RA)
A number of inflammatory conditions can affect the thyroid gland, each commonly described as thyroiditis (plural: thyroiditides):
acute suppurative thyroiditis (AST)
subacute lymphocytic thyroiditis (a.k.a. silent thyroiditis or painless subacute th...
Thyroid malignancies are most commonly primary thyroid cancers but can rarely be metastatic deposits.
Thyroid malignancies can be categorized into the following key subtypes:
primary thyroid cancers
papillary thyroid carcinoma: 60-80% of carcinomas
Tonsillitis refers to inflammation of any of the tonsils and is one of the most common head and neck infections in adolescents and young adults.
Patients may present with a variety of symptoms including painful throat (may be unilateral), dysphagia, fevers, tender cervica...
Torticollis (wryneck) is a clinical finding of head tilt with or without rotational spinal malalignment. It is not a diagnosis in itself and there are a wide range of underlying conditions. It is most common in the pediatric age group.
Torticollis can be acute (<1 week) or chronic (...
The Valsalva maneuver is the forced expiration of air against a closed airway, resulting in increased intra-abdominal, intrathoracic and pharyngeal pressure. It can be performed against a closed glottis or by one closing the mouth and pinching the nose while forcibly exhaling.
It is commonly us...
The vestibular line of Lapayowker refers to a vertical line passing down the most lateral aspect of vestibular apparatus. The petrous part of internal carotid artery lies medial to this line but lies lateral to it in the case of an aberrant internal carotid artery which is the characteristic ang...
Wackenheims line (also known as the clivus canal line or basilar line) is formed by drawing a line along the clivus and extending it inferiorly to the upper cervical canal.
Normally the tip of the dens is ventral and tangential to this line. In basilar invagination odontoid process transects th...