Head and Neck 1 Flashcards
cochlear aplasia
The labyrinth is abnormal with the cochlear absent (cochlear aplasia). The vestibule, semicircular canals and ossicles are present.
Cochlear aplasia, or complete absence of the cochlea is a rare anomaly which accounts for only 3% of cochlear malformations.
Radiographic features
- complete absence of the cochlea. Dense otic bone is seen at the anatomical site of the cochlea 2
- cochlear nerve canal and cochlear nerve are absent
- cochlear promontory is hypoplastic and flattened
- the vestibule and semicircular canals are often malformed, stunted, dilated but may be normal
- vestibular aqueduct is normal
- internal auditory canal usually hypoplastic
- facial nerve canal usually anomalous showing obtuse angle anterior genu
- middle ear is usually normal sized with normal ossicles
- oval window usually normal but may be atretic
Which benign H+N tumour is comprised of Epithelial and lymphoid cells.
Warthins Tumour
what is this?
- Congenital cholesteatoma
- 2% of temporal bone cholesteatomas
- can effect the middle ear, EAC, mastoid or petrous bone, or labyrinthe
- Most common location is the anterosuperior portion of the middle ear near the eustachian tube or stapes.
- CLinical
- young pt with normal mastoid pneumatization and without hx of chronic ear infections
- Histo
- squamous cell lining
- keratin debris
- cholesterol
rad features of this tumour
Typical location
- Rad Features of Glomus Vagale Paraganglioma tumours
- arises from paraganglia in the nodose ganglion of the vagus nerve in the nasopharyngeal carotid (or post-styloid parapharyngeal) space.
- displaces carotid anteromedially
- displaces jugular vein posterolateral and
- Does not splay the carotid bifurcation.
Glomus vagale tumours are paragangliomas 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.
Clinical presentation
Typically presents as a painless mass behind the carotid artery. Vocal cord paralysis is a relatively frequent finding (~47%) 3.
Location
Although they could occur at a similar position to carotid body tumours they tend to be more rostral in location and do not widen the carotid bifurcation. They displace the internal and external carotid arteries anteriorly, and the internal jugular vein posteriorly 1.
Case courtesy of Dr Ashwin M Polnaya, Radiopaedia.org, rID: 5926
Contents of Foramen Ovale
V3
accessory meningeal artery
Otic ganglion
Contents of Foramen Rotundum
V2
artery of foramen rotundum
emissary veins
What are Glomus tumours?
AKA
What do they arise from?
- Glomus tumors
- aka
- chemodectomas
- arise from chemoreceptor cells in multiple sites in the head and neck
- The majority are benign and approx 10% are multiple
- therefore it is important to check other common locations in the H+N during imaging
- GLomus tympanicum represents the. most common middle ear tumor
*
- Labyrinthitis ossificans
- ossification of the membranous labyrinth as a sequela of previous infections, inflammatory, traumatic or surgical injury to the middle ear.
- Seen as ossification within the membranous labyrinth on HRCT and foci of low signal on T2 with the otherwise high signal fluid of the membranous labyrinth
- Radiographic features
The scala tympani of the basal turn of the cochlea is the most commonly affected site 10.
CT
High-density bone deposition within the membranous labyrinth:
mild disease: hazy increase in density within fluid spaces of the membranous labyrinth
moderate disease: focal areas of bony encroachment on fluid spaces of the membranous labyrinth
severe disease: membranous labyrinth completely obliterated by bone replacing fluid spaces
MRI
loss of normal high signal of fluid within the membranous labyrinth is seen on heavily T2 weighted images (as low signal intensity foci in the labyrinth)
What is this?
- Klippel Fiel Syndrome:
- Cervical fusion
- short neck
- low posterior hairline
- limited cervical motion
Case courtesy of Dr Mohammad A. ElBeialy, Radiopaedia.org, rID: 23924
what does the anterior skull base consist of?
Broadly consists of floor of the anterior cranial foss and the roof of thenose, ethmoid air cells and orbits.
what is the pterygopalatine fossa
- an important space and potential rout of spread of disease in the deep face
- Contents
- Pterygopalatine ganglion
- Maxilary Nerve (V2) via foramen rotundum
- distal internal maxillary artery (via pterygomaxillary fissure)
Contents of the Optic Canal
3
- Optic Nerve
- Ohthalmic artery
- opthalmic veins
What are the different types of Glomus tumours?
4
types
- glomus jugulara:
- origin at the jugular bulb
- more common
- Glomus tympanicum
- arises from paraganglia along the inferior tympanic nerve (Jacobson nerve) frequently on the cochlear promontory
- Glomus vagale
- carotid body tumour
what does the central skull base consist of?
- floor of the middle crainal fossa,
- roof of the sphenoid sinus
- greater wing of sphenoid
what are the 2 types of fractures of the temporal bone?
which is more common?
Typically involves?
Which one involves the ossicles?
Which one involves the TM?
which is more likely to cause facial paralysis?
- Longitudinal Fractures
- red line
- 80% (more common)
- parallel to long axis
- Typically involves the middle ear
- The labrynth is typically spared
- The ossciles are usually involved (conductive hearing loss)
- The TM is is involved
- Facial paralysis 20%
- Transverse fractures
- Yellow line
- 20% (less common)
- Perpendicular to long axis
- Typially involves the inner ear
- The labyrinth is commonly involved
- the ossicles and TM are frequently spared
- Facial paralysis 50%
- A more clinically relevant classification may be otic capsule violating vs sparing.
- Otic capsule involvement increases the risk of sensorineural hearing loss, 7th CN palsy and CSF leak
- Fractures may also be oblique: ie mixed features of longitunial and transverse fractures, cross the petrotympanic fissure.
- Otosclerosis, also known as otospongiosis, is a primary osteodystrophy of the otic capsule (bony labyrinth of the inner ear). It is one of the leading causes of deafness in adults.
Terminology
The term otosclerosis is somewhat of a misnomer. Much of the clinical course is characterised by lucent rather than sclerotic bony changes and hence it is more appropriately known as otospongiosis which is a term preferred by many head and neck radiologists.
Contents of the vidian canal
- aka pterygoid canal
- vidian nerve
- vidian artery
- vidian vein
- connects PPF anteriorly to the foramen lacerum posteriorly
Petrous malformations a/w recurrent meningitis
- The presence of a fistula in the petrous portion of the temporal bone may lead to otorrhea, pneumocephalus, meningitis or abscess
- Acquired lesion of the petrous apex can potentially have similar complications depending on extent and violation of adjacent structures.
Craniodiaphyseal Dysplasia
Craniodiaphyseal dysplasia is a very rare autosomal recessive disorder which is typically presented in infancy and characterised by severe form of bone dysplasia, massive bone sclerosis and hyperostosis. This process of bone changes characteristically affects the facial bones resulting in severe facial deformity.
https://www.sciencedirect.com/science/article/pii/S2214541919300392
What are the complications of Acquired Cholesteatoma?
What complication/s are demonstrated here?
- Labyrinthine fistula
- dehiscence of semicircular canals
- usually the lateral one.
- Facial nerve paralysis
- 2ndary to involvement of the facial nerve canal
- Invasion of the tegmen tympani, petrous apex or sigmoid plate
- Automastoidectomy
Automastoidectomy denotes extensive bone destruction of the mastoid mimicking the appearance of surgery (mastoidectomy), most often caused by cholesteatoma.
Spontaneous evacuation of cholesteatoma can be seen with automastoidectomy 1. In these circumstances, it is often referred to as mural cholesteatoma or unusual cholesteatoma shell, as there is no residual soft tissue mass 2.
Automastoidectomy has also been reported with keratosis obturans 3.
https://radiopaedia.org/cases/automastoidectomy-with-labyrinthine-fistula
Automastoidectomy refers to extensive bony destruction of the mastoid forming one cavity resembling operative mastoidectomy. Cholesteatoma is the most common cause and this subtype is known as “mural cholesteatoma”.
Labyrinthine fistula refers to abnormal communication between inner ear perilymph and middle ear cavity on top of erosion or fracture of the bony labyrinth.
Treacher Collins syndrome
- atretic external auditory canal with hypoplastic middle ear and absent ossicles
- midline cleft palate
- underdeveloped zygomatic and pterygoid part
- hypoplastic mandible and maxilla
- anterior concavity of mandible
- hypoplastic left parotid
- parotid duct calculi
1 case question available
Case Discussion
In Treacher Collins syndrome, 1st and 2nd branchial arch structures are affected but the inner ear structures are normal.
Treacher colins Syndrome
- atretic external auditory canal with hypoplastic middle ear and absent ossicles
- midline cleft palate
- underdeveloped zygomatic and pterygoid part
- hypoplastic mandible and maxilla
- anterior concavity of mandible
- hypoplastic left parotid
- parotid duct calculi
1 case question available
Case Discussion
In Treacher Collins syndrome, 1st and 2nd branchial arch structures are affected but the inner ear structures are normal.
Gradenigo syndrome consists of the triad of:
petrous apicitis
abducens nerve palsy, secondary to involvement of the nerve as it passes through Dorello canal
retro-orbital pain, or pain in the cutaneous distribution of the frontal and maxillary divisions of the trigeminal nerve, due to extension of inflammation into Meckel cave
Pathology
Common pathogens are Pseudomonas and Enterococcus spp.
History and etymology
It was first described in 1907 by Giuseppe Conte Gradenigo (1859-1926), Italian otolaryngologist 2,3.
3 Places where lesions of the anterior skull base can arise from
- Centered in the bone
- arise in the anterior cranial fossa abvoe
- arise in the sinonasal cavities below
localisation of the lesion centre can help with the differential
Where from and to do the ossicles transmit sound waves
- Three ossicles transmit sound waves from the TM to the oval window in the vestibule.
contents of the carotid canal
Carotid artery
sympathetic plexus
- What are the contents of the jugular foramen
- contents of the jugular foramen
- pars nervosa
- IX
- Inferior petrosal sinus
- pars vascularis
- Jugular vein
- X
- XI
- pars nervosa
What syndrome is this found in?
Branchio-oto-renal (BOR) dysplasia,
Unwound cochlea. A, Axial CT image through the right cochlea of a patient with BOR demonstrates characteristic unwound dysmorphology with anteromedial rotation and displacement of the middle turn away from a tapered basal turn (arrow). B, Axial CT image through a normal right cochlea demonstrates normal apposition of the middle and basal turns (arrowhead).
http://www.ajnr.org/content/39/12/2345
Branchio-oto-renal (BOR) dysplasia, syndrome, or spectrum disorder is a rare syndromic disorder characterised by cervical branchial apparatus anomalies, ear malformations, and renal anomalies. If there are no renal anomalies, then it is more likely to be branchiootic dysplasia.
Pathology
When family history is absent, the diagnosis is established by 3 major criteria, or 2 major and 2 minor criteria 6. An affected individual with an affected first-degree relative only needs to meet one major criterion 6.
Major criteria, with examples 6-8:
- second branchial apparatus (arch/cleft) anomalies
- preauricular pits
- auricular malformation
- deafness (conductive, sensorineural, or mixed hearing impairment)
- renal anomalies
Minor criteria, with examples 6-8:
- preauricular tags
-
external auditory canal anomalies
-
middle ear anomalies
- ossicular chain malformations
-
inner ear anomalies
- cochlear anomalies, most commonly hypoplasia of the apical turn
- cochlear aperture stenosis
- dysplasia of lateral and/or posterior semicircular canals
- enlarged vestibular aqueduct
- abnormal course of the facial nerve
- other: facial asymmetry, palate abnormalities
Genetics
It carries an autosomal dominant inheritance. Most families with the branchio-oto-renal syndrome have mutations of the EYA1 gene, found on chromosome 8q.
Radiographic featuresCT
Specific features on temporal bone CT include the following:
- “unwound cochlea,” where the middle and apical turns are anteromedially rotated and displaced away from the basal turn 8
- medialized course of facial nerve (medial to cochlea) 9
Various additional findings on temporal bone CT are common 8,9:
- cochlear apical turn hypoplasia
- deficiency of the modiolus
- funnel-shaped internal auditory canal
- patulous Eustachian tube
Treatment and prognosis
Some individuals progress to end stage renal failure (ESRF) later in life.
What is the Sinus tympani?
what is its significance?
- The sinus tympani of the petrous temporal bone is a small recess in the posterior wall of the mesotympanum medial to the pyramidal eminence and stapedius muscle origin. Lateral to the pyramidal eminence is the facial recess.
- It is of surgical importance due to its invasion by cholesteatoma and difficulty in surgical visualisation.
- The pars flaccida cholesteatoma originates in Prussak space and usually extends posteriorly, while the pars tensa cholesteatoma originates in the posterior mesotympanum and tends to extend posteromedially.
*
Labrynthine aplasia:
aplasia or hypoplasia of otic capsule, petrous apex hypoplasia and other associated temporal bone abnormalities.
AKA Michel aplasia: historic terminology for complete labyrinthine aplasia.
Name that Syndrome:
- Coloboma
- heart anomaly
- choanal atresia
- mental retardation
- genital hypoplasia
CHARGE Syndrome
CHARGE syndrome. Axial CT image in a 6-day-old boy (a) shows bilateral bony and membranous choanal atresia with a thickened vomer and medial deviation of the lateral nasal walls at the level of the choanae (black arrows). There are secretions layering within the nasal cavities (*). Axial T2-weighted MRI at 4 days of age (same patient) (b) shows bilateral colobomas (arrowheads). Coronal T2weighted MRI (c) shows that the olfactory apparatus is absent on the right, but intact on the left (curved arrow). Axial CISS (constructive interference in steady state) image (c) shows bilateral absent semicircular canals and hypoplastic vestibules (white arrows). There is also bilateral cochlear nerve aperture and internal auditory canal stenosis
Otitis Media
what is it?
difference between adult and child cases?
- Otitis media
- fluid in the middle ear cavity
- types
- acute
- subacute
- chronic
- Children
- common
- Adults
- less common
- exclude nasopharyngeal carcinoma (NPC)
- which can cause eustchian tube obstruction and serous OM
Fig. 1—39-year-old man with nasopharyngeal carcinoma. A, Oblique T2-weighted MR image, parallel to eustachian tube extension, was obtained by locating eustachian tube on axial T2-weighted image. Diagonal lines denote reference lines. B, Oblique axial T2-weighted MR image, parallel to longitudinal axis of eustachian tube, was obtained using oblique sagittal T2-weighted MR image across eustachian tube. Diagonal lines denote reference lines. C–F, Oblique axial T1-weighted (C and E) and T2-weighted (D and F) MR images of eustachian tube were obtained before (C and D) and after (E and F) Valsalva maneuver. Small tumor (T) is shown in left pharyngeal recess (PR). Note pharyngeal opening of eustachian tube (POET), medial cartilage of eustachian tube (MCET), tensor veli palatine muscle (TVPM), levator veli palatine muscle (LVPM), and Ostmann fat pad (OF) on normal right side. After Valsalva maneuver was performed, both eustachian tubes opened normally, and air was visible in cartilaginous segment of eustachian tube (CET
https://www.semanticscholar.org/paper/Functional-MRI-of-the-Eustachian-Tubes-in-Patients-Mo-Zhuo/da4333c4369c61f030bf2bd37d2950b0b8051da4/figure/1
What are the segments of the Facial nerve?
- I love going to make over parties
- Intracranial/cisternal/intracannalicular
- Labyrinthine
- Geniculate
- Tympanic
- Mastoid
- Parotid
Camurati-Engelmann disease (CED) or progressive diaphyseal dysplasia (MIM 131300) is an autosomal dominant condition belonging to the group of craniotubular hyperostoses. Initially described by Cockayne in 1920,1 Camurati was the first to suggest its hereditary nature in 1922.2 In 1929, Engelmann reported a single case with muscular wasting and marked bone involvement.3 The name progressive diaphyseal dysplasia emphasises the progressive nature of the hyperostosis and the ever present involvement of the diaphyses,4 but currently, the eponym Camurati-Engelmann disease is widely accepted.
The hallmark of the disorder is the cortical thickening of the diaphyses of the long bones. Hyperostosis is bilateral and symmetrical and usually starts at the diaphyses of the femora and tibiae, expanding to the fibulae, humeri, ulnae, and radii. As the disease progresses, the metaphyses may become affected as well, but the epiphyses are spared.5 Sclerotic changes at the skull base may be present. The onset of the disease is usually during childhood and almost always before the age of 30. Most patients present with limb pain, muscular weakness, a waddling gait, and easy fatigability. Systemic manifestations—such as anaemia, leucopenia, and hepatosplenomegaly—occur occasionally.6 Abnormal values for several markers of bone formation and resorption have been reported in a few patients.7,8
Typical radiographs of CED patients from different families. (A) AP radiographs of both lower legs of a patient from family 14. There is cortical thickening and severe modelling defect at the diaphysis of both tibiae and fibulae. (B) Full leg radiograph (AP view) of a patient from family 2. Note the cortical sclerosis and the modelling defect with symmetrical distribution at the diaphyses of the femora, tibiae, and fibulae, with sparing of the metaphyses and epiphyses. (C) Radiograph of the left distal femur (AP view) of a patient from family 11. Cortical thickening at the diaphysis of the femur—especially at the medial aspect—results in a modelling defect. Note sparing of the metaphysis and epiphysis. (D) Plain radiograph of the right forearm (AP view) from a patient from family 5. Cortical sclerosis and modelling defect can be seen at both radius and ulna, but are most striking at the proximal diaphysis of the ulna. (E) Standard radiograph of the forearm of a patient from family 10. Marked cortical thickening at the diaphysis of the ulna and radius can be observed, causing obliteration of the medullary cavity and hypertrophy of the long bones. Note extension of the cortical sclerosis towards the distal metaphysis of the radius. (F) Radiograph of the right arm (AP view) of a patient from family 14. Thickening of the cortex of the diaphyseal portion of the humerus, ulna, and radius is present, resulting in narrowing of the medullary canal. Note also the modelling defect of the long bones, which is most extensive at the diaphysis of the ulna. (G) Radiograph of the left hand (AP view) of a patient from family 10, showing cortical sclerosis, cortical thickening, and medullary cavity obliteration at the diaphysis of metacarpals 2 and 3. (H) Radiograph of the skull (lateral view) of a patient from family 1. Sclerosis of the calvaria, the tympanic portion of the skull base, and the ascending ramus of the mandible is visible. Note relatively small frontal and sphenoidal sinuses resulting from adjacent sclerosis of the frontal bone and upper part of the face. The maxillary sinuses are spared.
What are the different congenital abnormalities of the inner ear?
- Cochlear incomplete partition Type 1
- cochlear incomplete partition type 2
- Cochlear hypoplasia
- cochlear aplasia
- labyrinthine aplasia
- common cavity malformation
- large vestibular aqueduct
- Small IAC
Rad features of this tumour
- Glomus Tympanicum
- Typically present as a small enhancing soft tissue mass centered of the cochlear promontory
- Enhancement distinguishes tumours from obstructive secretions
Left middle ear cavity glomus tympanicum paraganglioma (red arrow) located just anterior to the cochlear promontory (blue arrow).
Case Discussion
Right-sided middle ear soft-tissue lesion near the cochlear promontory. This lesion enhanced on MRI (not shown) consistent with a glomus tympanicum paraganglioma, which is the most common tumour of the middle ear cavity. These tumours can be asymptomatic, produce conductive hearing loss through contact with the ossicles (as in this case), or result in pulsatile tinnitus. This mass was observed to be stable over many years without treatment.
Cochlear incomplete partition type 1
a spectrum of abnormalities ranging from lack of internal structure of the cochlea to severe cystic cochleovestibular malformation.
The following are the defining CT features of incomplete partition type I, leading to the name cystic cochleovestibular malformation 1,2:
- cystic appearance of the cochlea due to
- absence of the modiolus including the base/cribriform plate between the cochlea and internal auditory canal (although a thin plate not visible on imaging may be present 5)
- absence of the interscalar septum
- grossly dilated vestibule
This appearance has been likened to a figure 8 morphology 6.
Several features have been associated but are not universal:
- no large vestibular aqueduct 1,4 (with exceptions 3)
- internal auditory canal enlargement 1 (with exceptions 4)
- semicircular canal dysplasia 3 (with exceptions 1)
- abnormal configuration of the left cochlea and vestibule which appear rudimentary with loss of their internal architecture and appear cystic.
- the semicircular canals appear dysplastic and of relatively small size compared to the contra-lateral side.
- normal right inner ear structures with intact vestibulo-cochlear system.
- no cerebello-pontine angle mass lesion.
- well-aerated aero-tympanic cavities and mastoid air cells on either side.
Case Discussion
Diagnosis - Left cystic cochleo-vestibular anomaly (CCVA) with dysplastic semicircular canals.
The Differential diagnosis includes
- common cavity - featureless common cavity with rudimentary cochlea, vestibule & semicircular canals
- cochlear aplasia - absent cochlea. The vestibule may be normal or hypoplastic.
- labyrinthine ossificans - acquired SNHL, usually post- meningitis. Dense bone fills membranous labyrinth including cochlea
- large endolymphatic sac anomaly (LESA) - cascading bilateral SNHL in 1st years of life. Bilateral large endolymphatic duct & sac with mild cochlear dysrnorphism.
- labyrinthine aplasia - absence of entire inner ear including cochlea, vestibule and semicircular canals (SCCs).
- SCC dysplasia - spectrum of anomalies; the most common appearance is short, dilated lateral SCC and vestibule forming single cavity
What is the signficance of the Fissula ante fenestram?
- The fissula ante fenestram (plural: fissula ante fenestras) is a small connective tissue-filled cleft in the otic capsule of the temporal bone, not typically visible on CT. The area around the fissula ante fenestram is the usual origin of fenestral otosclerosis.
Gross anatomy
The fissula ante fenestram is situated in the region anterior to the oval window 1. The structure is an irregular projection from the junction of the vestibule and scala vestibuli that extends to the periosteum of the middle ear just beneath the cochleariform process, where the tendon of the tensor tympani muscle turns laterally toward the malleus 2.
The fissula ante fenestram was previously thought to be related to the cochlear cleft 3, but recent studies have shown the latter to be a separate structure 4.
A structure called the fossula post fenestram is also described in histological studies and refers to a completely different but anatomically-proximate structure.
Anatomic trivia:
it is the only structure named fissula in the human body
it has not been found in any other animal
HRCT petrous bone, with axial plane parallel to the lateral semicircular canal. The FAF is just anterior to the stapedial footplate.
The fissula ante fenestram (FAF) lies anterior to the oval window, and parallel to the apical turn of the cochlea.
Case Discussion
CT petrous temporal bone with an axial plane parallel to the lateral semicircular canal. The important key structures at this level include the three ossicles (from anterior to posterior: malleus manubrium, incus long process and stapes crura), vestibule, footplate of the stapes in the oval window, cochlea (apical turn) and vestibular aqueduct. The illustration shows the fissula ante fenestram, the bony labyrinth and the space for the membranous labyrinth. The fissula ante fenestram located at the lateral wall of the vestibule (anterior to the oval window) and it stands parallel to the adjacent cochlear turn. Any curvilinear lucency at the fissula ante fenestram, should be considered as possible “fenestral otosclerosis” in adult, and “cochlear cleft” should be excluded in the paediatric age group.
- Klippel Fiel Syndrome:
- Cervical fusion
- short neck
- low posterior hairline
- limited cervical motion
Case courtesy of Dr Mohammad A. ElBeialy, Radiopaedia.org, rID: 23924
Name that Syndrome:
AR, macrocephaly, deafness, blindness. AD much less severe. May be asymptomatic
Osteopetrosis
Osteopetrosis, also known as Albers-Schönberg disease or marble bone disease, is an uncommon hereditary disorder that results from defective osteoclasts. Bones become sclerotic and thick, but their abnormal structure actually causes them to be weak and brittle.
Case courtesy of Dr Wael Nemattalla, Radiopaedia.org, rID: 7417
There are two separate subtypes of osteopetrosis:
Types of otospongiosis
- Fenestral:
- sclerosis or spongiosis around the oval window including fixation of stapes.
- Diagnosis is usually made from clinical and audiometric findings (conductive hearing loss)
- Begins as radiolucent focus at the anterior margin of the oval window.
- early disease may not be seen on imaging or may be very subtle
- Cochlear (retrofenestral):
- involves pericochlear bony labyrinth
- deossification around cochlear (lucent halo)
- sclerosis occurs later in disease
- mixed lucencies and densities.
- disease begins at fissula ante fenestram, fenestral bone alone most common (85%, conductive hearing loss), approximately 15% progress to cochlear (mixed hearing loss)
Confluent hypodense plaques of demineralisation partially surrounding the basal turns of both cochlea, yet sparing the middle and apical turns [Retrofenestral/Cochlear otospongiosis] (grade 2A - Symons and Fanning CT grading system), more on the left side.
Associated smaller hypodense plaques of demineralisation are seen at the left fissula ante fenestrum, representing fenestral otospongiosis.
Case Discussion
Case courtesy of Dr Bassem Marghany, Radiopaedia.org, rID: 67856
Otospongiosis represents the early/active phase of the disease, while otosclerosis represents the late/inactive phase.
In this case, the confluent hypodense plaques of demineralisation are partially surrounding the basal turns of both cochlea (pericochlear) [Retrofenestral/Cochlear otospongiosis] (grade 2A - Symons and Fanning CT grading system), more on the left side.
Associated smaller hypodense plaques of demineralisation are seen at the left fissula ante fenestrum, representing fenestral otospongiosis.
Craniometaphyseal dysplasia
https://www.nature.com/articles/ng0501_37?proof=t
The disease is characterized by defective metaphyseal remodeling that leads to massive metaphyseal widening of the long bones [1], [6], with a significant reduction in cortical thickness and osteoporosis [5], [6]. Pyle postulated a failure of bone resorption as the pathophysiological basis of the disease, which would lead to superposition of several layers of undermodeled bone at the metaphyseal segment [4].
- Bell Palsy
- acute onset of peripheral facial nerve palsy secondary to HSV
- usually resolves in 2-3 months
- Imaging performed for atypical or persistent palsy
- MRI
- enhancement along the facial nerve involving the intracanalicular (fundal tuft) and labyrinthine segments (that do not usually enhance).
- Mild enhancement of the tympanic and mastoid segments of thee facial nerve isnormal due to vascular supply
- facial nerve enhancement is non-specific and can occur in other inflammatory and neoplastic onditions
- especially if thenerve is enlarged consider secondary perineural spread of tumour
- Case 1 courtesy of Dr Roberto Schubert, Radiopaedia.org, rID: 14242
- Linear contrast enhancement at the apex of the left internal auditory canal.
case 2: Case courtesy of Dr Andrew Lawson, Radiopaedia.org, rID: 25296
Post contrast scans show vivid enhancement in the distal intracanalicular portion of the left facial nerve continuous with vivid enhancement in the left geniculate ganglion, which is slightly enlarged. Contrast enhancement then extends anteriorly into the left greater superficial petrosal nerve and posteriorly into the descending intrapetrous portion of the left facial nerve. No pathological enhancement detected elsewhere. In particular, no pial enhancement detected.
Malignant/necrotising external otitis
- Severe life threatening Pseudomonas aeruginosa infection in older adults with diabetes or chemo/rad patients
- Aggressive infection of EAC, adjacent soft tissues and skull base that spreads via cartilaginous fissures of Santorini and can extend into
- middle ear and mastoid air cells
- skull base
- phlegmon and abscesses may spread in any direction
- parapharyngeal
- parotid
- masticator
- intracranially
- Anterior to TMJ
Rad features
- thickened mucosa of EAC and soft tissue swelling
- bone erosion a/w opacification
- mastoiditis
- skull base OM
- Sinus phlebitis
- Sinus thrombosis
- Phlegmon or abscess in nearby soft tissues and spaces.
Case courtesy of Dr R Mannava, Radiopaedia.org, rID: 52590
Decreased density at the bone anterior to the oval window (fissula ante fenestram) bilaterally.
Case Discussion
Fenestral otosclerosis bilaterally. No involvement of the bone surrounding the cochlea.
10 neoplastic anterior Skull base lesions
- Meningioma
- Olfactory Neuroblastoma
- osteoma
- metastasis
- sinonasal SCC
- Sinonasal undifferentiated CA
- Sinonasal lymphoma
- Sinonasal melanoma
- Hemangiopericytoma
- Sinonasal nerve sheath tumour
Fibrous dysplasia of the inner ear
Fibrous dysplasia of the inner ear
Case courtesy of Dr Henry Knipe, Radiopaedia.org, rID: 75173
Asymmetric expansion of the right petrous temporal bone, mainly along the petrous ridge, with a ground-glass appearance of the bone matrix. Otic capsule structures, internal acoustic canal, middle ear cleft, external ear canal and mastoid air cells appear unaffected.
Case Discussion
This is an incidental finding of monostotic fibrous dysplasia on a petrous temporal bone CT. Compared to a CT brain from a year ago, there was no change. Temporal bone fibrous dysplasia is rare and is increasingly being discovered, as in this case, incidentally on imaging studies.
References
What are the branches of the facial nerve?
Intra-Temporal branches
Terminal Branches
- The intratemporal segment of the facial nerve gives rise to 3 branches.
- The extracranial segment of the facial nerve exits the skull through the Stylomastoid foramen and immediately gives off the posterior auricular nerve
- the main trunk then courses through the parotid gland and gives rise to 5 terminal branches
-
Intra-Temporal branches
- Greater petrosal nerve (lacrimation)
- Stapedius Nerve (stapedial reflex)
- Chorda tympani (taste)
- Posterior auricular nerve
-
Terminal
- Temporal
- Zygomatic
- Buccal
- Mandibular
- Cervical
Warthins tumours can occur in cervical LN’s
True or False?
True
Cochlear incomplete partition Type II
- incomplete partition with deficient interscalar septum between middle and apical turns
Cochlear incomplete partition type II (IP-II) is a type of inner ear malformation, specifically a cochlear incomplete partition, associated with sensorineural hearing loss. It is characterised by a cystic cochlear apex and should not be confused with Mondini anomaly, which is a historic term for the combination of incomplete partition type II, enlarged vestibule, and large vestibular aqueduct.
Radiographic featuresCT
The cochlea appears to have only 1.5 turns with coalescence of the apical and middle turn to form a cystic apex 1. The basal turn is normal, while these findings affect the middle and apical turns 2:
- absent interscalar septum
- absent osseous spiral lamina
- deficient modiolus
Incomplete partition type II is usually, but not always, associated with the extracochlear findings that contribute to the full Mondini anomaly:
- large vestibular aqueduct
- enlarged vestibule
What are the two parts of the external auditory canal?
- Cartilagenous portion
- bony portion
Contents of the Stylomastoid Foramen
- Cranial nerve VII
- Stylomastoid artery
Causes of Pulsatile Tinitus
- Normal vascular variants
- Aberrant ICA (case 1)
- Jugular bulb anomalies
- high jugular bulb
- dehiscent jugular bulb
- diverticulum
- Vascular tumors
- Glomus jugulare paraganglioma
- Glomus Tympanicum
- Vascular abnormalities
- Skull base dural AVF (case 2) /AVM
- Atherosclerotic carotid artery stenosis
- Carotid-Cavernous Fistula (CCF)
- ICA dissection
- ICA aneurysm at the petrous apex
- Fibromuscular dysplasia
- Dural sinus stenosis
- Transverse sigmoid sinus diverticulum
- Other
- idiopathic intracranial hypertension
- Paget disease
- otosclerosis
- meniere disease
Case courtesy of Dr Chris O’Donnell, Radiopaedia.org, rID: 38000
Contents of the hypoglossal canal
CN VII
Contents of the Superior orbital fissure
- Lacrimal n (V1)
- Frontal n (V1)
- trochlear (CN IV)
- superior div occulomotor nerve (CN III)
- Superior ophthalmic vein
- nasocillary n (V1)
- inferior div oculomotor nerve (CN III)
- inferior ophthalmic vein
- abducens (CN VI)
What are the parts of the Temporal bone?
The temporal bone is divided into five portions
- Mastoid
- posterolateral part
- includes mastoid process, the attachment for the SCM
- Petrous
- pyramidal shaped medial part
- inner ear structures
- IAC
- petrous apex
- Squamous
- anterolateral part
- forms the lateral wall of the middle cranial fossa
- Tympanic
- forms bulk of EAC
- middle ear space
- Styloid
coalescent mastoiditis
coalescent mastoiditis
Coalescent mastoiditis is simply the term given to acute otomastoiditis when mucoperiosteal disease extends to involve the bone. The septae which normally separate one mastoid air cell from another are resorbed. This change is only easily appreciated on thin section bone-algorithm through the temporal bones. Comparison to the contralateral mastoid may be useful in detecting early changes, although normal asymmetry should be taken into account.
Complications (see acute otomastoiditis article) are much more likely once infection spreads to the bone, and include periauricular cellulitis and intracranial extension.
Case courtesy of Assoc Prof Frank Gaillard, Radiopaedia.org, rID: 4870
right tinitus
Case courtesy of Dr Khalid Alhusseiny, Radiopaedia.org, rID: 75701
There is a vascular loop of the right anterior inferior cerebellar artery (AICA) where the artery is reaching the distal half of the internal auditory canal (IAC).
Other associated findings include partly empty sella and expanded Meckel’s cave bilaterally.
Case Discussion
Tinnitus may be classified according to its nature as arterial pulse synchronous type (pulsatile) or a continuous (nonpulsatile) type.
Pulsatile tinnitus is most frequently the result of a vascular abnormality or a vascular tumor. However, in some cases, the etiology of tinnitus remains uncertain, and most of these patients have no imaging abnormalities.
Compression of the vestibulochoclear nerve by vascular structures has been proposed as a possible cause of tinnitus. However, controversial results have been reported in the medical literature about the relationship between neurovascular compression of the nerve and neuro-otologic symptoms like vertigo and tinnitus.
Magnetic resonance imaging (MRI) is the most appropriate method for noninvasive evaluation of the microvascular structures in this region, using 3D-gradient echo (GRE) sequences with high resolution such as fast imaging employing steady-state acquisition (FIESTA) and constructive interference in steady state (CISS) sequences.
The vascular loop can be divided into three anatomical groups based on location:
Type I: CPA (cisternal segment).
Type II: Proximal half of the IAC.
Type III: Distal half of the IAC.
Semicircular canal dehiscence syndrome
CT shows a small defect or dehiscence in the bony wall of the superior or less commonly the posterior SCC.
Seen as >2mm dehiscence of roof of superior SCC on coronal or ideally Transverse oblique Ct reformats for SCC dehiscence.
Clinically presents with dizziness and vertigo +/- nystagmus with lound sound or pressure (Tullio phenomenon). Clinical syndrome + positive CT = SCC dehiscence syndrome.
Can also be a/w inner ear conductive heading loss.
The cause is unknown likely developmental. possibly also secondary to trauma.
Cholesterol granuloma
- AKA cholesterol Cysts
- mix of
- hemorrhage,
- cholesterol crystals and
- granulation tissue
- that may be present in temporal bone, including the petrous apex or rarely the middle ear.
- Depending on the location of the expansile erosive lesion and inveloment of critical structures they can be a/w hearing loss, tinnitus and CN palsies.
- mix of
- Radiographic features
- expansile erosive osseous lesion of the petrous apex
- smooth margins
- CT
- isodense relative to brain,
- no enhancement,
- no calc
- MRI
- hyperintense to brain on T1 bc of methemoglobin and cholesterol crystals
- retains high signal on fat sat T1 distinguishing them from fatty lesions
Rad features of carotid body paraganglioma tumours
Rad features of carotid body paraganglioma tumours
- arises from carotid glomus bodies (paraganglia)
- splays the external carotid artery and internal carotid arteyr
Case courtesy of Assoc Prof Frank Gaillard, Radiopaedia.org, rID: 4627
Does mucoepidermoid carcinoma commonly cause perineural spread?
True or false?
2019 path Q.
Case courtesy of Assoc Prof Frank Gaillard, Radiopaedia.org, rID: 36047
Mucoepidermoid carcinoma (MEC) is the most common type of minor salivary gland malignancy in adults. Mucoepidermoid carcinoma can also be found in other organs, such as bronchi, lacrimal sac, and thyroid gland. Mucicarmine staining is one stain used by pathologist for detection.
Mucoepidermoid carcinoma of salivary glands
Dr Mohamed Saber and Assoc Prof Frank Gaillard◉◈ et al.
Mucoepidermoid carcinoma is a tumor that usually occurs in the salivary glands. It can mimic most other tumors of the glands, and therefore is often considered in the differential.
Epidemiology
Mucoepidermoid carcinomas are seen throughout all adult age groups but are most common in middle age (35-65 years of age) 5. However, it is the most common malignant salivary gland tumor of childhood 4-5. Overall, mucoepidermoid carcinomas account for 1,5:
2.8-15.5% of all salivary gland tumors:
1-10% of all major salivary gland tumors
6.5-41% of minor salivary gland tumors
In the parotid gland, they are the most common malignant primary neoplasm. A slight female predilection has been described, and radiation has been implicated as a risk factor 5.
Clinical presentation
Mucoepidermoid carcinomas most frequently arise in the parotid gland, and presents as a painless swelling, with or without facial nerve involvement. These tumors can however be found anywhere there are salivary glands. Overall distribution across various glands is as follows 5:
major salivary glands: ~50% *
parotid gland: ~40%
submandibular gland: ~7%
sublingual gland: ~3%
minor salivary glands: ~50%
palate: most common
retromolar trigone
floor of the mouth
buccal mucosa
lip
tongue
other: anywhere in the proximal aerodigestive tract, the lacrimal glands and even in the bronchi 2,5
As such, presentation will depend on the anatomic location.
Pathology
The tumors are composed of a mixture of:
mucus secreting cells (muco-)
squamous cells (-epidermoid)
lymphoid infiltrate often also present 3
Histology
Histology will often show clear mucin containing cells, which stain reddish pink with the mucicarmine stain. Mucoepidermoid tumors are graded histologically into:
low grade:
well-differentiated cells with little cellular atypia
high proportion of mucous cells
prominent cyst formation
intermediate grade: intermediate features
high grade
poorly differentiated with cellular pleomorphism
high proportion of squamous cells
solid with few if any cysts
Case courtesy of Assoc Prof Frank Gaillard, Radiopaedia.org, rID: 4298
DDx benign Temporal bone tumours
what is this tumour?
- meningioma
- facial schwannoma
- may arise anywhere along the course of Cn VIII
- in the IAC, the tumour may be indistinguishable from a vestibular schwannoma unless it can be seen to arise from the facial nerve
- osteoma
- adenoma
- benign but locally aggressive, rare
- Endolymphatic sac tumour (image)
- benign but locally aggressive
- permeative destructive lesion with spiculated calcified tumour matrix
- Epidermoid
- primary cholesteatoma
- not a true neoplasm
- primary cholesteatoma
- Case courtesy of Dr Bruno Di Muzio, Radiopaedia.org, rID: 27278
Contents of the inferior orbital fissure
- Inferior Orbit Gets Infra-Orbital Nerves and VeinZ
- Inferior Ophthalmic vein (Tributary to Cavernous sinus and pterygoid Venous Plexus)
- Ganglionic branches (from ppf to V3)
- ION infraorbital nerve (branch of V2)
- A infraorbital Artery (branches of maxillary artery)
- V infraorbital vein (drains inferior orbit, communicates with inferior ophthalmic vein, tributary to pterygoid venous plexus)
- Zygomatic nerve (branch of V2)
DDx Malignant temporal bone tumours
- Squamous cell carcinoma arising from the EAC
- Adenocarcinoma
- lymphoma
-
Metastases
- breast
- lung
- renal
- prostate
- neuroblastoma (paeds)
- Leukemia (paeds)
- Chondrosarcoma (image)
- Rhabdomyosarcoma (paeds/teens)
Case Discussion
https://radiopaedia.org/cases/temporal-bone-chondroblastoma
This case demonstrates a chondroblastoma (“Codman tumour”) in a very unusual localisation.
Temporal bone chondroblastomas are rare benign osseous tumours with very low prevalence (1-2%). They can be commonly found in all bones with endochondral ossification, but mostly in the epiphysis and/or metaphysis of long bones in young patients (2nd decade). The growth pattern of chondroblastoma differs from other entities affecting the temporal bone and should be differentiated from other temporal bone lesions. The patients usually complain of pain in the area, swelling and neurological symptoms such as facial nerve palsy. Common imaging modalities are CT and MRI. Microscopic and immunohistochemical analysis complete the diagnosis.
Differential diagnoses are clear cell chondrosarcoma, chondromyxoid fibroma and giant cell tumour. Furthermore eosinophilic granuloma (Langerhans cell histiocytosis) and enchondroma. Specific for the temporal bone lesions are: confluent apical petrositis, cholesterol granuloma, plasmocytoma and temporal bone rhabdomyosarcoma.
The treatment approach differs depending on the location of the tumour and on the grade of the expansive/destructive pattern.
Small underdeveloped cochlear < 2 turns typically
Stenotic right internal auditory canal. Cystic right cochlear apex with only 1.5 turns. The cochlear aperture is narrow and hypoplastic.
Hypoplastic right vestibule with an absent lateral semicircular canal.
Both vestibular aqueducts are normal.
The bony facial canals are well seen on both sides being relatively narrower on the right side.
Traces of mucosal thickening are seen at both maxillary and ethmoidal sinuses.
Case Discussion
This case demonstrates cochlear hypoplasia as one of the inner ear malformations that consist of only one turn or a partial cochlear turn, abnormally small internal acoustic canal; the vestibule and semicircular canals are usually malformed.
osteogenesis imperfecta of the temporal bone
Initial axial (A) and direct coronal (B) high-resolution CT scans of the temporal bones through the level of the labyrinthine segment of the facial nerve (axial) and the cochlea (coronal) processed with a bone algorithm (2-mm section thickness; 512 × 512 matrix). The facial nerve canal showed slight irregularities along the labyrinthine segment (arrowhead) but otherwise appeared normal. Bandlike, undermineralized areas around the cochlea can be seen (arrowheads).
A female patient had several episodes of fractured limbs after minor trauma in her childhood. Family medical history revealed that her mother had a history of recurrent bone fractures. Genetic findings when the patient was 10 years old confirmed the diagnosis of OI type I (2). At 24 years old, she presented with bilateral progressive hearing loss. Clinical examination revealed blue sclerae and loose joints. Otoscopy showed normal tympanic membranes bilaterally. A pure-tone audiogram demonstrated profound sensorineural hearing loss on the right side and severe sensorineural hearing loss on the left side. The conductive hearing and vestibular functions were within the normal range. Tympanometry was normal in both ears. The stapedius reflex could not be elicited. The functions of both facial nerves were normal.
A high-resolution CT scan postprocessed with a bone algorithm and viewed with wide windows at that age showed symmetrical, abnormal bandlike areas of lucency surrounding the cochlea. The facial nerve canal showed minimal irregularities along the labyrinthine segment on both sides, but otherwise appeared normal (Fig 1). When the patient was 26 years old, sensorineural hearing loss on the left side progressed and the conductive hearing functions were additionally impaired on both sides. Facial nerve functions were still normal. A CT scan at that age demonstrated a progression of the bandlike undermineralized pericochlear areas, now extending from the promontory to the apical turn of the cochlea. The round window niche was now filled with thickened and undermineralized bone. Further profound progression was present along the labyrinthine and proximal tympanic segments of the facial nerve canal and in the geniculate gangion, which were indistinct and irregular bilaterally (Fig 2). The mastoid segment of the facial nerve canal was normal.
what are the differences between Sinus and Attic Cholesteatomas with regards to the following:
location
part of TM affected
direction of ossicle displacement
part of ossicle erosion
area of bone errosion
Sinus cholesteatomes are from the pars tensa and located in the sinus tympani. Ossicles are displaced laterally. Bone erosion is initially subtle. Ossicle erosion occurs at the short process of the incus and stapes.
With Attic cholesteatomas, they arise from the pars flacida in prussak’s space. Ossicles tend to be displaced medially. Bone erosion occurs at the lateral tympanic wall with erosion of the scutum being an early finding. Ossicle erosion tends to occur at the head of the malleus and long process of the incus.
Osteopetrosis is a heterogeneous group of skeletal disorders. It is a rare genetic disease caused by osteoclast dysfunction, leading to invalid bone desorption and remodeling and an increase in skeletal mass and density. We present the case of a 52-year-old female with osteopetrosis of the temporal bone. She reported loss of hearing in her left ear 14 years ago because of a head trauma. Four months ago, she was conservatively treated because of sudden sensorineural hearing loss in her right ear with no improvement. Her pure tone average audiogram was bilaterally 90 dB with 10% speech recognition. The patient was implanted with a cochlear implant. Except for the extremely thick and dense cortical bone of the mastoid, surgery was uneventful. Speech recognition 6 months after the surgery showed 75%. The results were stable for 3 years follow-up. Patients with profound hearing loss caused by osteopetrosis may benefit from cochlear implantation.
Szymański, Marcin et al. “Osteopetrosis of the Temporal Bone Treated with Cochlear Implant.” The journal of international advanced otology 11 2 (2015): 173-5 .
Craniodiaphyseal dysplasia
https://jmg.bmj.com/content/jmedgenet/27/11/701.full.pdf
Craniodiaphyseal dysplasia is a very severe bone dysplasia characterised by massive generalised hyperostosis and sclerosis, especially involving the skull and facial bones. Progressive bony encroachment upon cranial foramina leads to severe neurological impairment in childhood.
Contents of the foramen Lacerum
- Not a true foramen
- Nerve of the pterygoid canal (formed by the greater petrosal and deep petrosal nerves)
- Terminal (meningeal) branches of ascendign pharyngeal artery
- emissary veins
Radiographic features of Cholesteatoma?
How do you distinguish Choelsteatoma from chronic OM?
- SOft tissue mass in middle ear
- Erosion of incus and scutum common (otic spur)
- BOne resportion (collagenase) is typical and occurs most commonly in:
- ossicles
- Lateral SCC (can lead to fistula)
- tegmen typmpani
- Facial Canal
- Mastoid air cells may be under pneumatized and sclerotic secondary to chronic infection
- Labyrinthine fistula formation in the Lateral SCC
- it is often impossible to distinguish chronic middle ear infection from cholesteatoma in cases with little bone destruction on CT.
- However MRI can be useful for distinction of cholesteatoma (restricted DWI, no enhancement) from inflammatory changes or granulation tissue (enhances)
Case courtesy of Dr Jeremy Jones, Radiopaedia.org, rID: 26812
Contents of foramen spinosum
- Middle meningeal artery
- meningeal (recurrent) branch of the mandiubular nerve
- occasionally the the lesser petrosal nerve
Acute mastoiditis refers to a suppurative infection of the mastoid air cells. It is the most common complication of acute otitis media.
The left mastoid air cell are opacified as is the middle ear with partial destruction of the ossicular chain.
The petrous temporal bone contains a mixture of lucent and sclerotic with destruction of the medial cortex close to the petrous apex.
Case Discussion
An extreme example of two pathologies. A profound mastoiditis with intracranial extension, causing a huge cerebellar abscess, with a resultant hydrocephalus.
The patient went to surgery immediately, with no residual neurological deficit after surgery.
Case courtesy of Dr Ian Bickle, Radiopaedia.org, rID: 26284
Terminology
In acute otitis media, an inflammatory middle ear effusion is present that can freely move into the mastoid air cells. Consequently, some authors comment that a mild mastoiditis is technically present in nearly all cases of acute otitis media 6. The mere presence of mastoid fluid on imaging, however, does not change the management of otherwise uncomplicated acute otitis media. Thus, many clinicians reserve the diagnosis for when there are clinical signs or symptoms of inflammation involving the mastoid. When mastoiditis and acute otitis media occur concurrently, sometimes the term acute otomastoiditis is used.
When there is clinical evidence of acute mastoiditis, the initial stage is referred to as acute mastoiditis with periostitis, incipient mastoiditis, or mild mastoiditis 6,7. When mucoperiosteal involvement evolves into resorption of mastoid bony septa, this stage is referred to as coalescent mastoiditis. Coalescent mastoiditis is a radiological diagnosis.
What are the divisions of the middle ear?
- Epitympanum
- attic
- above imaginary line between scutum tip and tympanic facial nerve
- Mesotympanum
- middle ear proper
- between epitympanum and hypotympanum
- Hypotympanum
- shallow space below imaginary line between tympanic annulus and cochlear promontory
Paget Diseaes of the inner ear
Paget’s disease in a patient with bilateral hearing loss, right worse than left. A and B, Axial CT scan demonstrates exuberant medullary expansion of the skull, temporal bones, and base of the skull. Several scattered sclerotic foci most prominent near vertex and severe thinning of the outer cortex is noted (white arrow). Note demineralization resulting in expansion of the petrous apex (asterisks) and thinning of bone around the right otic capsule (black arrowhead), which is more pronounced on the right versus the left. Note narrowing of the right internal auditory canal due to new bone deposition (black arrow)
https://www.researchgate.net/figure/Case-2-Pagets-disease-in-a-patient-with-bilateral-hearing-loss-right-worse-than_fig3_316896273
Rad features of this tumour
- centered in the region of the jugular foramen
- most common path of spread is to the middle ear.
- accompanied by permeative bone changes in the jugular foramen
- characteristic findings by MRI are multiple low signal intensity areas that represent flow void in the tumour
- this has a salt and pepper appearance.
Case courtesy of Dr Prashant Mudgal, Radiopaedia.org, rID: 27037
- Intensely enhancing hyperdense lesion is seen involving the left jugular foramen, measuring approximately 3.5 x 3.5 x 3.5 cm. The lesion is causing destruction and widening of the jugular foramen.
Medially the lesion has intracranial extra dural extension in the posterior fossa indenting the cerebellar cortex.
Laterally the lesion is extending in the middle ear cavity (epi, meso and hypotympanum)and external auditory canal. There is erosion of the long process of incus, inferior semicircular canal and the basal turn of cochlea and the lateral wall of tympanic segment of facial nerve.
Lesion is infiltrating the jugular bulb and inferiorly extending into the proximal jugular vein. Posterior inferiorly there is destruction of the basi occiput and lateral aspect of foramen magnum.
Case Discussion
The most common tumour to develop in the jugular foramen is a paraganglioma (glomus jugulare). Paragangliomas in the skull base are ubiquitous in their distribution and arise from paraganglia or glomus cells situated at the following sites:
(1) in the adventitia of the jugular bulb beneath the floor of the middle ear
(2) in the bony walls of the tympanic canals related to the tympanic branches of the IX and X nerves
(3) in the bone of the promontory, close to the mucosal lining of the middle ear.
Imaging studies are necessary to depict the location and extent of tumour involvement, to help determine the surgical approach, and to predict operative morbidity and mortality.1
What does the inner ear consist of?
- The inner ear AKA labyrinth consists of:
- three semicircular canals
- connect to the vestibule
- Vestibule
- utricle
- saccule
- lies between the semicircular canals and cochlear
- Cochlear
- sensorineural hearing
- connects to stapes and oval window
- round window (allows for counterpulsation of fluid)
- three semicircular canals
- The base of the stapes rocks in and out against the membrane in the oval window.
The vibrations are transmitted from the oval window via the endolymph to the hair cells of the organ of Corti in the cochlea.
The round window dissipates the pressure generated by the fluid vibrations within the cochlea and thus serves as a release valve.
what are the types of Cholesteatoma and their causes + rarity?
- Mass of straified squamous epithelium and keratin debris
- Cause
- epithelial cells accumulate in the middle ear via a perforation of the TM.
- The most accepted theory is that they arise from TM retraction pockets resulting from decreased intratympanic pressure.
- Types
- acquired 98%
- chronic middle ear infection (common)
- Arise in attic (prussak space, pars flaccida cholesteatoma)
- or from pars tensa (sinus tymapni)
- Congenital
- Epidermoid
- 2%
- cholesteatoma arises from epithelial nests in middle ear, mastoid or petrous bone including the labyrinth (uncommon)
- acquired 98%
- https://radiopaedia.org/cases/petrous-apex-cholesteatoma-1
- A right petrous apex well-defined lobulated border S.O. lesion is seen. It measures 3.2 X 1.8 X 1.9 cm in its main axial and CC diameters respectively. The lesion shows hypointense T1 and bright T2 signal with incomplete nullification of its signal in the FLAIR sequence. The lesion is hyperintense in DWI series. It is slightly hypointense to isointense to the brain in ADC map. The lesion shows no significant post-contrast enhancement but for subtle / if any marginal enhancement. The lesion is seen mildly compressing the right internal auditory canal the right facial and vestibule-cochlear nerves as well as the right cerebello-pontine angle and abutting the right inferior temporal lobe.
Case Discussion
Right petrous apex mass lesion - which most likely represents a petrous apex cholesteatoma.
A cholesteatoma will not usually attunuate on FLAIR imaging, however partial attenuation, as seen here, is not uncommon.
Name that Syndrome:
- Facial asymmetry
- microtia
- variable ocular abnormalities
- cervical spine deformity
Goldenhar syndrome
aka Hemifacial macrosomia
Indications for surgery in temporal bone fracture?
what is this?
- Ossicular fracture or dislocation
- facial nerve injury
- frequently conservative but occasionally requires surgical decompression
- Labyrinthine fistula - surgery if persistant
- CSF leaks - surgery if persistant
DDx for this tumour?
Case courtesy of Dr Matt A. Morgan, Radiopaedia.org, rID: 32560
Acinic cell carcinoma (salivary glands)
Dr Yuranga Weerakkody◉ et al.
Acinic cell carcinomas of the salivary glands are rare malignant neoplasms that account for 1-3% of all salivary gland tumors.
Pathology
Pathology may superficially resemble normal serous (acinar) cells of the salivary glands. It is considered a low-grade, indolent malignancy, but with a tendency to recur after excision 4.
Location
The majority arise in the parotid gland (81-98% 3) and they may be bilateral and multicentric.
Radiographic features
Imaging findings in acinic cell carcinoma are non-specific and there is an overlap with benign tumors such as Warthin tumor and pleomorphic adenoma 6.
CT
non-specific appearance
hypoattenuating regions of central necrosis
irregular enhancing solid component
MRI
non-specific appearance
T2 hyperintense cystic/necrotic component
solid component is also mildly T2 hyperintense
well-marginated
irregular solid component that enhances on the postcontrast sequence
Features that might suggest malignancy include:
lymphadenopathy
rapid increase in size
clinical history of pain
Treatment and prognosis
Surgical excision is considered the standard of care. Acinic cell carcinomas may recur in up to 35% of patients 5.
Differential diagnosis
Possible differential considerations include:
Warthin tumor: much more common
pleomorphic adenoma: much more common
mucoepidermoid carcinoma: more common than acinic cell
adenoid cystic carcinoma: more common than acinic cell
What are the contents of the IAC?
- Contents of the IAC are divided by the falciform crest and Bills bar
- Facial nerve (CN VII)
- anterior+superior
- Cochlear nerve (CN VIII)
- anterior + inferior to falciform crest
- Superior vestibular nerve (CN VIII)
- superior and posterior
- inferior vestibular nerve (CN VIII)
- inferior and posterior
- Facial nerve (CN VII)
Cleidocranial dysostosis
Case courtesy of Dr Sharifah Intan, Radiopaedia.org, rID: 31114
Cleidocranial dysostosis (CCD), also known as cleidocranial dysplasia, is a rare skeletal dysplasia with predominantly membranous bone involvement, which carries an autosomal dominant inheritance 4.
Clinical presentation
large head, with large fontanelles with delayed closure
broad mandible
supernumerary teeth
high arched palate
neonatal distress due to thorax being narrowed and bell shaped
excessively mobile and drooping shoulders
may have genu valgum and short fingers
Pathology
It is a rare polyostotic skeletal dysplasia caused by a mutation in CBFA1 gene in AD inherited or sporadic mutation pattern (in approximately 40%) which is characterised by incomplete intramembranous ossification of midline skeletal structures inclusive of the clavicle as well as a defective development of the pubic bones, vertebral column, and long bones 5.
Radiographic features
Plain radiograph
Skull
multiple wormian bones
widened sagittal sutures and/or fontanelles
premature fusion of the coronal suture (brachycephaly)
frontal and/or parietal bossing
basilar invagination (atlantoaxial impaction)
persistent metopic suture
supernumerary or abnormal teeth
abnormal ear structures with hearing loss 6
Chest
hypoplasia/aplasia of the lateral clavicle (absent clavicles): may have two separate hypoplastic segments 5
supernumerary ribs
hemivertebrae with spondylosis
small and high scapulae
Pelvis
hypoplasia of iliac bones
absent/delayed ossification of the pubic bone creating the appearance of a pseudo-widening of the symphysis pubis
Limbs
short/absent fibula
short/absent radius
coxa vara
hypoplastic terminal phalanges
pseudoepiphysis of metacarpals and metatarsal bones
What is the most common parotid tumour and what is its known risk factor.
Pleomorphic adenoma is a common benign salivary gland neoplasm characterised by neoplastic proliferation of parenchymatous glandular cells along with myoepithelial components, having a malignant potentiality. It is the most common type of salivary gland tumor and the most common tumor of the parotid gland.
Introduction
Pleomorphic adenoma, the most common salivary gland tumor, is also known as benign mixed tumors (BMT’s), because of its dual origin from epithelial and myoepithelial elements.It is the commonest of all salivary gland tumors constituting up to two-thirds of all salivary gland tumors.[1][2][3]
Go to:
Etiology
The etiology of pleomorphic adenoma is unknown, but the incidence of this tumor has been increasing in the last 15-20 years in relation to the exposure of radiation. One study suggests that oncogenic simian virus (SV40) may play a role in the onset or progression of pleomorphic adenoma. Prior head and neck irradiation is also a risk factor for the development of these tumors. [4]
https://www.ncbi.nlm.nih.gov/books/NBK430829/
Case:
https://radiopaedia.org/cases/pleomorphic-adenoma-and-dentigerous-cyst
What are the boundaries of the anterior and central skull base?
- Medial: posterior margin of planum sphenoidale (tuberculum sella)
- Lateral: lesser wing. of sphenoid
boundaries of the PPF
- Anterior:
- posterior maxillary sinus wall
- Posterior
- pterygoid plates
- inferior part of LWoS
- superior
- infraorbital fissue
- inferior
- tapers into the greater palatin canal
- lateral
- pterygomaxillary fissure to the infratemporal fossa
- medial
- perpendicular plate of the palatine bone
- sphenopalatine foramen superiorly
Ramsaym hunt syndrome
- Herpes zoster of the facial nerve
Ramsay Hunt syndrome (RMS), also known as herpes zoster oticus, is shingles of the facial nerve. It is due to reactivation of the varicella zoster virus in the geniculate ganglion.
Ramsay Hunt syndrome classically presents with a triad of 3,4:
otic pain
facial nerve palsy
a vesicular eruption (often painful) involving the external auditory canal, pinna, tongue or hard palate
There may be involvement of the vestibulocochlear nerve (CN VIII) in which case vertigo, sensorineural hearing loss, and tinnitus may be present.
Pathology
The syndrome is due to latent infection of the geniculate ganglion with varicella zoster virus and subsequent reactivation.
Radiographic features
Imaging is identical to that seen in Bell palsy, with increased enhancement of the facial nerve. Care should be taken not to mistake normal facial nerve enhancement on MRI for that observed in Ramsay Hunt syndrome.
History and etymology
This eponymous syndrome was named after James Ramsay Hunt, an American neurologist (1872-1937) 2.
large vestibular aqueduct: >1mm diameter at midpoint and /or ?2mm at operculum perpendicular to long axis of vestibular aqueduct. Rule of thumb: abnormal if larger than the posterior SCC.
High incidence of associated cochlear abnormalities.
Enlargement of the vestibular aqueduct and its contents is the most common component of congenital inner ear dysplasias. It is more often bilateral than unilateral and is associated with the Mondini malformation of the cochlea in about 8% of cases 1.
What are the boundaries of the middle ear?
- Lateral
- Tympanic membrane
- Consists almost entirely of the tympanic membrane. In upper part, consists of lateral wall of epitympanic recess.
- Roof
- Consists of thin layer of bone- Tegmen tympani. Separates the middle ear from the middle cranial fossa.
- medial
- forms lateral wall of internal ear.
Most prominent structure is a round bulge.
Promontory formed by base of cochlea,which has an associated plexus of nerves- Tympanic plexus.
- forms lateral wall of internal ear.
Tympanic plexus is formed by tympanic branch of Glossopharyngeal nerve – branches from Internal Carotid Plexus
The Lesser petrosal nerve is a branch of the Tympanic plexus which leaves the middle ear from the foramen ovale to relay in Otic ganglion.
- posterior
- facial nerve recess
- pyramidal eminence
- sinus tympani
It is only partially complete. In lower part, bony partition between tympanic cavity and mastoid air cells.
* Superiorly, epitympanic recess is continuous with aditus to Mastoid antrum. Structures related
Pyramidal eminence-elevation for entry of Stapedius
Opening for entry of Chorda Tympani
- anterior
- Partially complete. In lower part, thin layer of bone separating tympanum from Internal Carotid artery.
Structures related
- Partially complete. In lower part, thin layer of bone separating tympanum from Internal Carotid artery.
Opening for Pharyngotympanic tube
Smaller opening for canal containing tensor tympani
Foramen for exit of Chorda Tympani
- Floor
- Thin layer of bone which separates it from the Internal Jugular vein. Near medial border of floor, through a small aperture, tympanic branch of Glossopharyngeal nerve enters.
Where do cholesteatomas usually occur?
which reformat (ie axial, sag, cor) is the area best assessed?
The lateral epitypmpanic recess AKA Prussaks Space.
Complications of Otitis Media
- Meningitis
- subdural empyemea
- epidural abscess
- Dural venous sinus thrombosis
- Petrositis
-
Gradenigo Syndrome (image 2)
- osomastoiditis
- CN VI palsy
- Pain in distribution of CN V
- Subperiosteal or Bezold abscess (image 1)
- Focal encephalitis, Brain abscess,
- otitic hydrocephalus
Common cavity malformation: undifferentiated cochlear and vestibule represented by a common cavity of variable size
What syndrome is this found in?
Unwound cochlea. A, Axial CT image through the right cochlea of a patient with BOR demonstrates characteristic unwound dysmorphology with anteromedial rotation and displacement of the middle turn away from a tapered basal turn (arrow). B, Axial CT image through a normal right cochlea demonstrates normal apposition of the middle and basal turns (arrowhead).
Branchio-oto-renal (BOR) dysplasia, syndrome, or spectrum disorder is a rare syndromic disorder characterised by cervical branchial apparatus anomalies, ear malformations, and renal anomalies. If there are no renal anomalies, then it is more likely to be branchiootic dysplasia.
Pathology
When family history is absent, the diagnosis is established by 3 major criteria, or 2 major and 2 minor criteria 6. An affected individual with an affected first-degree relative only needs to meet one major criterion 6.
Major criteria, with examples 6-8:
- second branchial apparatus (arch/cleft) anomalies
- preauricular pits
- auricular malformation
- deafness (conductive, sensorineural, or mixed hearing impairment)
- renal anomalies
Minor criteria, with examples 6-8:
- preauricular tags
-
external auditory canal anomalies
-
middle ear anomalies
- ossicular chain malformations
-
inner ear anomalies
- cochlear anomalies, most commonly hypoplasia of the apical turn
- cochlear aperture stenosis
- dysplasia of lateral and/or posterior semicircular canals
- enlarged vestibular aqueduct
- abnormal course of the facial nerve
- other: facial asymmetry, palate abnormalities
Genetics
It carries an autosomal dominant inheritance. Most families with the branchio-oto-renal syndrome have mutations of the EYA1 gene, found on chromosome 8q.
Radiographic featuresCT
Specific features on temporal bone CT include the following:
- “unwound cochlea,” where the middle and apical turns are anteromedially rotated and displaced away from the basal turn 8
- medialized course of facial nerve (medial to cochlea) 9
Various additional findings on temporal bone CT are common 8,9:
- cochlear apical turn hypoplasia
- deficiency of the modiolus
- funnel-shaped internal auditory canal
- patulous Eustachian tube
Treatment and prognosis
Some individuals progress to end stage renal failure (ESRF) later in life.
Name that syndrome:
- Thyroid organification defect with goitre
- inner ear malformation
Otologic features of Pendred syndrome in patient. (A) Enlarged vestibular aqueduct of patient compared with normal individual (white arrows). (B) Mondini defect: absence of middle turn of the cochlea and smaller cochlea in our patient compared with normal individual (narrow white arrow-apical turn, wide white arrow-middle turn, black arrow-basal turn of the cochlea).
