Submandibular gland enlargement refers to an increase in the volume of the submandibular gland, exceeding "normal" values of 7.4 ± 1.8 mL 1.
submandibular duct stenosis (e.g. tumor, granulomatous disease)
acute sialadenitis: following ...
Optic nerve calcification is a rare radiological finding, with only a short differential diagnosis, many of which have only been described in isolated case reports 1-4.
optic nerve meningioma
optic nerve head drusen
idiopathic dural optic nerve sheath calcification
Maxillodental leave alone lesions are usually incidental findings that do not require treatment nor follow-up if the patient is asymptomatic.
This article includes findings from orthopantomogram, cone-beam CT, and sinus CT studies.
Do not touch:
Leave alone lesions of the skull base refers to incidental findings that do not require treatment nor follow-up.
This article includes findings from brain CT, HRCT of the temporal bone, and MRI studies.
Do not touch:
arrested pneumatization of the skull base - sphenoid benign fatty lesion 1
Leave alone lesions are findings that are usually discovered incidentally and do not require any specific treatment or follow-up if the patient is asymptomatic.
This article includes findings from paranasal sinus CT and MRI studies.
Epiglottic enlargement is often seen on lateral neck radiographs and it's accepted to confirm clinical suspicion of acute epiglottitis only on this finding 1. However, an enlarged epiglottitis has a wide range of differentials that should be considered.
Optic canal enlargement can be caused by numerous etiologies.
The optic canal has an average transverse diameter of 3.6 ± 0.6 mm 1. The optic canal can be considered enlarged when it is >6.5 mm in transverse diameter 4.
glioma of optic nerve
meningioma of optic nerve shea...
Periapical radiolucencies are commonly observed findings on OPG and other dental/head and neck imaging modalities.
They can represent a number of pathologies:
periapical lucency related to apical periodontitis
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
Lacrimal sac masses are very uncommon and more commonly have a malignant (~80%) rather than benign (~20%) etiology.
granulomatosis with polyangiitis
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.
Possible causes include:
trauma (temporal bone f...
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.
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...
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
Calcification of the external ear (auricular cartilage) may arise from a number of causes, including:
gout and pseudogout
osteoprotegerin (OPG)-deficiency juveni...
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...
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:
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)
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.
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...
There are many causes for mandibular periostitis:
Langerhans cell histiocytosis
malignancy (both primary and metastatic)
necrosis, e.g. radiation osteonecrosis
Garre's sclerosing osteomyelitis
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 u...
Torticollis, also known as wry neck, 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 wee...
Medical devices in the head and neck are regularly seen by radiologists on plain film, CT and MRI. 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 is a short list of causes for enlarged extraocular muscles. The differential can be narrowed by the clinical history, known systemic illness, pattern of specific muscles involved, the muscle morphology, as well as concurrent findings outside the muscles 3:
inflammatory, infectious, and 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.
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 ...
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
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
Developmental orbital cysts correspond to a heterogeneous group of congenital orbital developmental anomalies with a cystic component, ranging from closed sacs lined by an ectodermal epithelium, such as epidermoid and dermoid, to neoplasms such as teratoma 1:
choristoma: benign tumors formed by...
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-orbitoethmoidal (NOE) fractures
Heterogeneous echogenicity of the thyroid gland is a non-specific finding and is associated with conditions diffusely affecting the thyroid gland. These include:
The presence of heterogenous thyroid echogenicity may reduce sensitivity of detection of thyro...
Pulsatile exophthalmos, a.k.a. pulsatile proptosis, is a clinical symptom characterized by protrusion - i.e. exophthalmos (proptosis) - and pulsation of the eyeball that can occur due to various causes:
neurofibromatosis type 1 (with sphenoid wing dysplasia) 2
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...
Proptosis (rare plural: proptoses) refers to forward protrusion of the globe with respect to the orbit. Proptosis can be relative (to the contralateral eye), comparative (to a prior measurement of the same eye), or absolute (based on normal population reference values).
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):
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
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...
Differential diagnosis for calcified masses in the mandible includes:
calcifying odontogenic cyst (Gorlin cyst)
calcifying epithelial odontogenic tumor (Pindborg tumor)
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
Cervical lymphadenopathy in an adult can result from a vast number of conditions. They include:
from head and neck tumors
other neoplastic lesions
There is a wide differential diagnosis of petrous apex lesions:
asymmetrical marrow/asymmetrical pneumatization
fat signal intensity on all sequences
petrous apex cephalocele 4
CSF signal intensity on all sequences
Ocular metastases, also termed uveal metastases, account for over 80% of all ocular pathology, and need to be distinguished from extraocular metastasis, which are quite different groups of tumors.
This article will discuss metastatic lesions affecting the orbits. For other intracranial metastat...
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 ...
Parotid gland 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 a standard surgical sieve approach into infective, inflammatory, immune, neoplastic, infiltrative, and congenit...
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...
Orbital vascular lesions may be difficult to distinguish on imaging. However, the following conditions have been described:
arteriovenous malformation (AVM)
orbital lymphangioma / lymphangiovenous malformation / venolymphatic malformation
The differential diagnosis of pediatric cervical lesions is commonly encountered in practice, unfortunately, the list is long.
Most lesions tend to be inflammatory 3:
non-tuberculous mycobacterial lymphadenitis
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...
Enlargement of the optic nerves is uncommon. Swelling of the optic nerves has a surprisingly broad differential.
optic nerve glioma
optic nerve meningioma
involvement by retinoblastoma
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 are:
trigeminal schwannoma: most common,...
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
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)
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
A pedunculated intratracheal mass has a variety of differential diagnoses:
benign tumor, e.g. hamartoma, chondroma, lipoma
metastasis to tracheal mucosa, e.g. renal cell carcinoma, melanoma
polyp, e.g. inflammatory, antrochoanal
An orbital mass carries a wide differential.
lacrimal gland or duct tumors
rhabdomyosarcoma of the orbit
optic nerve meningioma
optic nerve glioma
schwannoma (of trigeminal or other cranial nerves except optic)
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...
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
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...
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
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...
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
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 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, ...
The differential for cystic parotid lesions includes:
bilateral cystic parotid lesions
benign lymphoepithelial lesions of HIV
dysgenetic polycystic disease of salivary glands
unilateral cystic parotid lesion(s)
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...