Petrous

Question 1

40. Which of the following is the most common cause of pulsatile tinnitus?

A. Glomus tumour

B. Cholesterol granuloma

C. Dehiscent jugular bulb

D. Carotid artery dissection

E. Meningioma

Answer 1

A. Glomus tumour

Glomus tumour is the most common cause of pulsatile tinnitus.

Question 2

49) A 24-year-old male patient presents following a head injury with GCS of 13. There is bruising over the right temporal region. A CT scan shows no intracranial haemorrhage but does identify a longitudinal fracture through the petrous temporal bone. What complication should be considered?

a. sensorineural hearing loss

b. conductive hearing loss

c. vertigo

d. carotid artery injury

e. sigmoid sinus injury

Answer 2

b. conductive hearing loss

Longitudinal fractures of the temporal bone represent 75% of temporal bone fractures and run parallel to the axis of the petrous pyramid. They may cause dislocation of the auditory ossicles, usually the incus, causing a conductive deafness.

Sensorineural hearing loss is associated with transverse fractures of the temporal bone, as is vertigo.

Facial nerve palsy is seen in both fracture types, but is less common in longitudinal fractures, where it frequently recovers spontaneously.

Carotid artery and major sinus injuries are not directly associated with petrous temporal fractures.

Question 3

56) A 30-year-old female presents with left-sided hearing loss and facial nerve palsy. CT shows a solid mass in the left middle ear behind an intact tympanic membrane, occupying enlarged attic & eroding scutum and ossicles. What is the most likely diagnosis?

a. Bell’s palsy

b. cholesteatoma

c. malignant otitis externa

d. acoustic neuroma

e. squamous cell carcinoma

Answer 3

b. cholesteatoma

Cholesteatoma is an abnormal collection of keratinized debris arising from an ingrowth of stratified squamous epithelium and occurs in primary (2%) or acquired (98%) types.

The acquired type can be further subdivided, with the most common being a primary, acquired, epidermoid-type lesion of the pars flaccida, located in the attic of the middle ear.

Cholesteatomas are benign lesions but cause bone erosion, including the auditory ossicles, resulting in conductive hearing loss.

Local extension may compress the geniculate ganglion in the facial canal.

Question 4

49 A patient presents with unilateral hearing loss. CT. demonstrates a non-dependent expansile mass within the middle ear with bony erosion of the sigmoid sinus plate, scutum and ossicles. MR imaging reveals that the mass has high signal on both T1 weighted fat saturation and T2 weighted acquisitions. What is the diagnosis?

(a) Glomus tumour

(b) Cholesteatoma (congenital)

(c) Cholesteatoma (acquired)

(d) Cholesterol granuloma

(e) Schwannoma

Answer 4

(c) Cholesteatoma (acquired)

A cholesterol granuloma is an inflammatory mass of granulation tissue due to recurrent haemorrhage into the middle ear. Characteristically, there is high signal on both T1-fat saturation imaging and on T2- weighted imaging

Question 5

35 A patient with facial numbness has an MRI of the brain. A lesion lying entirely within the cavernous sinus is revealed. Given this location, which of the following cranial nerves is least likely to be involved?

(a) Oculomotor

(b) Trochlear nerve

(c) Abducens nerve

(d) The first division of the trigeminal nerve

(e) The third division of the trigeminal nerve

Answer 5

(e) The third division of the trigeminal nerve

The cavernous sinus contains the III, IV, V1, V2 and VI cranial nerves.

Question 6

@# 5. Which of the following is a feature of a 15-year-old boy with juvenile angiomyofibroma?

A. Posterior bowing of the posterior antral wall

B. Invasion of the frontal sinuses

C. Widening of the superior orbital fissure

D. Delayed enhancement on CT

E. Intermediate SI on T1 with punctuate areas of Hyperdensity

Answer 6

C. Widening of the superior orbital fissure

Widening of the pterygopalatine fossa with anterior bowing of the posterior antral wall, invasion of the sphenoid sinus (in 2/3), widening of the superior and inferior orbital fissures, and immediate enhancement after contrast injection are all features. On MR, punctuate hypodensities on T1 are due to the highly vascularised stroma.

Question 7

@# 13 A middle-aged man presents with an acute onset facial nerve palsy and has MR imaging with the i. v. administration of gadolinium. Which of the following features would support the diagnosis of a Bell’s palsy?

(a) Enhancement of the tympanic portion of the facial nerve

(b) Enhancement of the intracanalicular portion of the facial nerve

(c) Enhancement of the mastoid portion of the facial nerve

(d) Continuing symptoms at 9 months

(e) Demineralisation of the petrous apex

Answer 7

(b) Enhancement of the intracanalicular portion of the facial nerve

Although non-specific, enhancement of the intracanalicular and labyrinthine portion occurs in Bell’s palsy (other inflammatory and neoplastic conditions should also be considered).

Enhancement of the tympanic and mastoid portions of the facial nerve is a normal variant.

Demineralisation does not occur.

Question 8

42 Which two cranial nerves are most commonly affected by skull base injury?

(a) I and II

(b) III and IV

(c) V and VI

(d) VII and VIII

(e) IX and X

Answer 8

(a) I and II

The olfactory (I) and optic (II) nerves are most often affected by skull base injury.

Question 9

44 A male adolescent suffers from recurrent epistaxis and the subsequent imaging investigations reveal a likely juvenile angiofibroma. Regarding this condition, which of the following statements is incorrect?

(a) The majority extend within the sphenoid sinus

(b) The majority extend within the pterygopalatine fossa

(c) Embolisation may be undertaken via the maxillary artery.

(d) Biopsy should be performed prior to therapy to confirm the diagnosis

(e) The lesion may recur following treatment.

Answer 9

(d) Biopsy should be performed prior to therapy to confirm the diagnosis

The vascular nature of the tumour contraindicates biopsy.

Question 10

49 A young man is involved in an RTA and arrives in hospital with a markedly reduced GCS. CT imaging reveals a fracture of the temporal bone. Which of the following features would be more typical of a transverse, rather than longitudinal fracture of the temporal bone?

(a) Facial nerve palsy

(b) Involvement of the ossicles

(c) Bleeding from the external auditory canal

(d) Sparing of the labyrinth

(e) Involvement of the tympanic membrane

Answer 10

(a) Facial nerve palsy

Longitudinal fractures are parallel to the axis of the petrous pyramid and predominantly affect the middle ear (including the ossicles and tympanic membrane). Transverse fractures are perpendicular to the axis of the petrous pyramid and affect the labyrinth. Facial nerve palsy occurs in 50% of transverse fractures, but only 20% of longitudinal fractures

Question 11

56 A patient presents with left sided proptosis. A CT reveals a low-density mass causing expansion of the frontal sinus. There is focal thinning of the bony walls, dehiscence of the orbital roof and mass effect on globe. No enhancement with i.v. contrast medium. What is the most likely diagnosis?

(a) Rhinosinusitis

(b) Allergic fungal sinusitis

(c) Sinonasal polyposis

(d) Mucocoele

(e) Nasopharyngeal carcinoma

Answer 11

(d) Mucocoele

A mucocoele is the accumulation of mucous secretions behind an obstructed ostium. This causes expansion of the sinus cavity and bone remodelling. Differentiation from carcinoma can be difficult

Question 12

58 A child with fever and otalgia has a CT examination performed. There is opacification of both the middle ear and mastoid. Fluid levels can be seen. There is bony resorption of the mastoid and haziness of the air cell walls. What is the most appropriate description?

(a) Acute mastoiditis

(b) Coalescent mastoiditis

(c) Bezold’s abscess

(d) Osteomyelitis

(e) Subperiosteal abscess

Answer 12

(b) Coalescent mastoiditis

This is a description of coalescent mastoiditis.

A Bezold’s abscess represents extension of infection down into the tissues of the neck.

Question 13

@# 59 A patient presents with pulsatile tinnitus. CT reveals a mass in the left temporal bone and there is focal uptake with 111 1n octreotide imaging. Which of the following is least likely?

(a) Glomus tympanicum

(b) Meningioma

(c) Carcinoid metastasis

(d) Small cell cancer metastasis

(e) Metastasis of papillary carcinoma of the thyroid

Answer 13

(e) Metastasis of papillary carcinoma of the thyroid

Octreotide is a somatostatin analogue, and uptake is seen where somatostain receptors are expressed, such as neuroendrocine tumours (e.g., glomus tympanicum), and other malignancies (e.g., small cell lung cancer, lymphoma, and breast cancer). There is also uptake in a few tumours that do not express the receptor (e.g., meningioma, astrocytoma).

Question 14

61 You are reporting an MR of the nasal sinuses, and you notice a mass within the right maxillary sinus. The request card reads: ‘? squamous cell carcinoma? mucocoele/secretions.’ Which of the following features would be more supportive of a diagnosis of benign disease, rather than squamous cell carcinoma?

(a) Bony destruction

(b) Low T2W signal

(c) Peripheral enhancement

(d) Heterogeneous MR signal intensity

(e) Occupational exposure to nickel

Answer 14

(c) Peripheral enhancement

Squamous cell carcinoma is usually of heterogeneous, low T2W signal, with a solid enhancement pattern. Bony destruction is seen in approximately 80% of sinonasal casecs at first presentation. Occupational exposure to nickel, chrome pigment and the use of Bantu Snuff are recognized risk factors.

Question 15

@# (Ped) 82) A 13-year-old male presents with recurrent epistaxis. CT shows a highly vascular mass in the nasopharynx, with widening of the pterygopalatine fossa and invasion of the sphenoid sinus. Which arterial branch is the feeding vessel likely to be arising from?

a. ascending pharyngeal

b. facial artery

c. superficial temporal artery

d. internal maxillary artery

e. internal carotid artery

Answer 15

d. internal maxillary artery

Juvenile angiofibromas are the commonest benign tumour of the nasopharynx and can grow to enormous sizes. They tend to present in teenagers with recurrent and severe epistaxis, as well as nasal obstruction. They are highly vascular and biopsy is contraindicated. In most cases, they are supplied primarily by the internal maxillary artery

Question 16

16.A 45 year old woman undergoes investigation for conductive hearing loss. History reveals several previous ear infections. Direct visualization with an otoscope shows a mass behind an intact tympanic membrane. Coronal CT imaging demonstrates a soft-tissue mass located between the lateral attic wall and the head of the malleus. There is blunting of the scutum. The mass does not enhance post-contrast. What is the most likely diagnosis?

a. Chronic otitis media

b. Cholesterol granuloma

c. Cholesteatoma

d. Rhabdomyosarcoma

e. Squamous cell carcinoma

Answer 16

16.c. Cholesteatoma

A cholesteatoma consists of a sac lined with stratified squamous epithelium and filled with keratin – essentially ‘skin growing in the wrong place’. They can be acquired (98%) or congenital (2%). Most acquired cholesteatomas arise in the superior portion of the tympanic membrane (pars flaccida) and extend into Prussak’s space where they can cause medial displacement of the head of the malleus and erosion of the bony scutum. The characteristic imaging feature of a cholesteatoma is bone erosion associated with a non-enhancing soft-tissue mass. Complications can be intratemporal and intracranial:
Intratemporal: ossicular destruction, facial nerve paralysis, labyrinthine fistula, complete hearing loss, automastoidectomy. Intracranial: meningitis, sinus thrombosis, abscess, CSF rhinorrhea

Question 17

29. A 58 year old man presents with impaired vision and intractable headaches. He has a past history of recurrent sinusitis. Examination reveals left-sided proptosis and a palpable mass in the superomedial aspect of the orbit. CT demonstrates a soft-tissue mass causing expansion and erosion of the left frontal sinus. There is peripheral enhancement post-contrast injection. The next radiological step should be:

a. Referral to an appropriate clinician – you have made a confident diagnosis of a benign aetiology

b. MRI of the head and neck – you have made a confident diagnosis of a malignant aetiology and wish to stage its local spread

c. MRI of the head and neck – you are unsure of the nature of the aetiology and want to further characterise it

d. Perform a staging CT – you are concerned this may be metastatic disease

e. Perform an ultrasound scan of the orbit – to further characterise the lesion

Answer 17

29. a. Referral to an appropriate clinician – you have made a confident diagnosis of a benign aetiology

This is almost certainly a mucocoele. Mucocoeles represent the end stage of a chronically obstructed sinus. They most commonly affect the frontal sinus (60%), with ethmoid (30%), maxillary (10%) and sphenoid (rare) following respectively. Patients present with symptoms as described in the question. Increased intrasinus pressure results in expansion and erosion of the sinus walls. There may be a surrounding zone of bone sclerosis. Contrast injection typically reveals rim enhancement, which helps to differentiate from the more solid enhancement pattern of neoplasms.

Question 18

(Ped) 43. A teenage boy with a history of nasal speech is investigated for recurrent severe epistaxis. The ear, nose and throat surgeon suggests the possibility of a juvenile angiofibroma. Which of the following CT findings would you consider typical for this lesion?

a. A highly vascular nasal mass causing widening of the pterygopalatine fissure

b. A relatively avascular fibrous nasal mass centred over Little’s area

c. A vascular mass centred over the pterygopalatine fossa best demonstrated on delayed imaging

d. A fibrous mass extending posteriorly into the middle cranial fossa with relatively little bone erosion

e. A centrally located, highly vascular mass causing extensive septal destruction

Answer 18

43. a. A highly vascular nasal mass causing widening of the pterygopalatine fissure

Juvenile angiofibromas are the most common benign nasopharyngeal tumour. They occur almost exclusively in teenage males. In most cases CT allows accurate diagnosis, although MRI may be used pre-operatively to assess soft-tissue involvement. The tumours typically start in the pterygopalatine fossa and cause local bone erosion. On CT, the presence of a nasal mass and a widened pterygopalatine fissure is pathognomonic of the condition. The tumour may invade the sphenoid sinus, the middle cranial fossa (via the superior orbital fissure), the orbit (via the inferior orbital fissure), the infratemporal fossa, or extend through the sphenopalatine foramen. The tumour may be very fibrous but tends to be highly vascular such that it only enhances immediately after bolus injection. Biopsy is therefore contraindicated. Angiography is not required to obtain the diagnosis but may be utilised for pre-operative planning or during therapeutic embolisation.

Question 19

QUESTION 8
A young patient undergoes CT of the paranasal sinuses. The main finding is an enhancing nasal mass with widening of the left pterygopalatine fissure. What is the most likely diagnosis?

A Adenoid cystic carcinoma

B Angiofibroma

C Angiosarcoma

D Inverting papilloma

E Lymphoma

Answer 19

B Angiofibroma

A nasal mass with widening of the pterygopalatine fissure is pathognomonic of juvenile angiofibroma

Question 20

QUESTION 67
A 36-year-old man with a history of asthma and hay fever presents with loss of smell and recurrent headaches. CT of the paranasal sinuses shows several rounded masses in the maxillary sinuses and nasal cavity with enlargement of the ostia of the maxillary antra bilaterally. The bones appear normal. What is the most likely diagnosis?

A Inverting papillomas

B Mucocoeles

C Nasal granulomas

D Nasal polyps

E Squamous carcinoma

Answer 20

D Nasal polyps

Nasal polyposis is common in adults. The polyps may cause widening of the nasal airway and/or maxillary antra.

Question 21

QUESTION 76
A 59-year-old man presents with conductive hearing loss on the right side. CT reveals a non-enhancing mass in the middle ear which is suspicious for an acquired cholesteatoma. Which one of the following is a well recognized complication of this condition?

A Ankylosis of the ossicular chain

B Erosion of the lateral semicircular canal

C Middle ear effusion

D Opacification of the mastoid air cells

E Osteomyelitis of the temporal bone

Answer 21

B Erosion of the lateral semicircular canal

An acquired cholesteatoma is a mass of epithelial debris within the middle ear, leading to conductive hearing loss. It can result in several complications: destruction of the ossicles, destruction of the tegmen tympani causing a cerebral abscess or meningitis, labyrinthine fistula due to erosion of the lateral semicircular canal and facial paralysis secondary to facial nerve involvement.

Question 22

19. A 35-year-old man presents with tinnitus and hearing loss in the right ear. Investigations include an MRI of the internal auditory meati. This demonstrates an expansile lesion in the right petrous apex, without bone destruction. The lesion is of increased signal on T1WI, increased signal on T2WI, and non-enhancing. What is the most likely diagnosis?

A. Cholesteatoma.

B. Petrous apex cephalocele.

C. Mucocele.

D. Petrous apicitis.

E. Cholesterol granuloma.

Answer 22

19. E. Cholesterol granuloma.

The findings described are typical of cholesterol granuloma. A critical distinction is between this and a petrous carotid artery aneurysm, which may show similar features of increased T1WI signal. However, the presence of flow void, lesion centred on the carotid canal, and additional complex areas of signal due to blood products of varying ages might be expected in an aneurysm.
A petrous apex cephalocele is an area of fluid signal (hypointense T1WI, hyperintense T2WI) adjacent to the petrous apex that is in communication with Meckel’s cave. A mucocele of the petrous apex may cause benign bony expansion and is typically of decreased signal on T1WI and increased signal on T2WI, and is non-enhancing. A cholesteatoma may have similar T1WI and T2WI signal characteristics, but these entities may be differentiated by DWI. On DWI, cholesteatoma is typically of increased signal, whereas a mucocele is of decreased signal. Petrous apicitis is an aggressive process that typically enhances with gadolinium and is secondary to infection. There may be an accompanying history of infection, middle ear disease, diabetes, or immunocompromise.

Question 23

24. A 45-year-old man has a severe head injury and is noted to have a left facial nerve palsy. Following stabilization, a subsequent HRCT scan of the temporal bone is performed. This demonstrates a fracture of the left temporal bone, involving the course of the left facial nerve. Which orientation of fracture and which segment of the facial nerve are most likely to be involved?

A. Transverse/internal auditory canal.

B. Longitudinal/internal auditory canal.

C. Transverse/labyrinthine.

D. Longitudinal/labyrinthine.

E. Transverse/mastoid.

F. Longitudinal/mastoid.

Answer 23

24. C. Transverse/labyrinthine.

Transverse temporal bone fractures are more commonly associated with facial nerve paralysis (approximately up to 50%) than longitudinal temporal bone fractures (approximately up to 20%). The labyrinthine segment is the most likely segment of the facial nerve to be associated with facial paralysis.

Question 24

38. A 15-year-old male presents with a history of recurrent epistaxis and nasal obstruction. MRI demonstrates a lesion centred at the sphenopalatine foramen, which is hypointense on T1WI and heterogeneously intermediate signal on T2WI. Intense lesional enhancement and multiple flow voids are noted on post-gadolinium T1WI. What is the diagnosis?

A. Ludwig angina.

B. Nasopharyngeal carcinoma.

C. Inverted papilloma.

D. Juvenile angiofibroma.

E. Glomus jugulare.

Answer 24

38. D. Juvenile angiofibroma.

Juvenile angiofibromas are benign but locally aggressive tumours with high vascularity. They typically occur in adolescent boys and present with recurrent epistaxis and nasal obstruction. They are centred within the sphenopalatine foramen and involve the pterygopalatine fossa, producing a bowed appearance of the posterior wall of maxillary sinus and widening of pterygopalatine fossa, inferior orbital, and pteryogomaxillary fissures. Osseous erosion is commonly seen. The specific differentiating feature on MRI is the presence of multiple flow voids on T2WI and enhanced T1WI

Question 25

39. A 50-year-old male presents with a history of intermittent epistaxis, nasal obstruction, and frontal headache. He undergoes a CT of the sinuses that demonstrates an isodense soft-tissue mass filling the right maxillary antrum with extension through the infundibulum into the nasal cavity. There is associated bony remodelling of the infundibulum. On MRI, the mass is isointense to muscle on T1WI and T2WI, and demonstrates a convoluted cerebriform pattern on enhanced T1WI. The remainder of the sinuses are unremarkable. What is the diagnosis?

A. Juvenile angiofibroma.

B. Inverted papilloma.

C. Antrochoanal polyp.

D. Invasive fungal sinusitis.

E. Nasal carcinoma.

Answer 25

39. B. Inverted papilloma.

Inverted papillomas are uncommon benign epithelial neoplasms with significant malignant potential. They arise from the lateral nasal wall or maxillary sinus. They are most commonly seen in 40-70-year-olds with a male to female ratio of 2-4:1. CT demonstrates a soft-tissue mass centred in the middle meatus associated with bone remodeling. Stippled calcification is seen in 20% of cases. On MRI, it is isointense on T1WI and iso/hypointense on T2WI. Heterogenous enhancement is seen in 50% of cases. A convoluted cerebriform pattern on T2WI or enhanced T1WI is typical of inverted papillomas. J. angiofibromas are seen in younger patients and are located in the post. Nasal cavity demonstrating intense enhancement and flow voids on MRI. Antrochoanal polyps are homogenously hyperintense on T2WI. Invasive fungal sinusitis is primarily seen in immunosuppressed patients. They are frequently bilateral. CT f ndings include complete opacification of sinuses by hyperdense mass, erosion or remodelling of sinuses, and intrasinus calcification. T2 hypointense. Carcinomas cause bone erosion/destruction rather than remodelling.

Question 26

40. A 45-year-old female patient presents with recurrent frontal sinusitis following functional endoscopic sinus surgery (FESS). Which of the following CT findings is not commonly associated with postoperative frontal recess stenosis?

A. Inadequate removal of the agger nasi and frontal recess cells.

B. Retained superior portion of the uncinate process.

C. Medialization of middle turbinate.

D. Osteoneogenesis due to chronic inflammation or mucosal stripping.

E. Scarring or inflammatory mucosal thickening.

Answer 26

40. C. Medialization of middle turbinate.

FESS is the treatment of choice for patients with medically refractory sinusitis. Obstruction of the frontal recess is the main cause for medically refractory frontal sinusitis. The frontal recess is considered a difficult area to treat with FESS and it is also prone to re-stenosis. All of the above options are commonly associated with postoperative frontal recess stenosis except medialization of middle turbinate. Medialization (Bolgerization) is performed to treat a lateralized middle turbinate, which is a well-recognized cause of frontal recess stenosis.

Question 27

12 A 65-year-old man attended the ENT outpatients complaining of a one-year history of unilateral tinnitus and vertigo. Audiology confirmed a unilateral sensorineural hearing loss on the affected side. An MRI scan demonstrated a mass that was thought to be an acoustic neuroma. What signal characteristics are most likely?

a Hyperintense on T1-weighted images

b Enhancement following gadolinium

C No enhancement following gadolinium

d Hypointense on T2-weighted images

e Isointense to grey matter on T2-weighted images

Answer 27

12 Answer B. Enhancement following gadolinium

Acoustic neuromas are also known as vestibular schwannomas and are the most common tumours of the cerebellopontine angle. They arise from the perineural Schwann cells of the vestibular division of the VIII cranial nerve and are usually unilateral. In Type II neurofibromatosis they are, by definition, bilateral. A vestibular schwannoma displays the characteristic imaging appearances that are common to all schwannomas; on CT imaging they are isointense with brain parenchyma, exhibiting enhancement post contrast and containing cystic components. On MRI the lesion is isointense with brain parenchyma on T1 W images, hyperintense on T2 and displays enhancement post gadolinium

Question 28

9 A 17-year-old male patient with recurrent left-sided epistaxis and associated mucopurulent discharge was investigated urgently in ENT outpatients. He underwent a CT scan which revealed a unilateral, low-attenuation mass filling the left maxillary sinus with extension into an expanded nasal cavity and middle meatus. A subsequent MRI also showed the mass, which appeared bright on T2-weighted images and displayed peripheral enhancement following IV gadolinium. What is the most likely diagnosis?

a juvenile angiofibroma

b Mucocele of the maxillary sinus

C Nasopharyngeal carcinoma

d Antrochoanal polyp

e Inverted papilloma

Answer 28

9 Answer D: Antrochoanal polyp

An antrochoanal polyp is a benign expansile lesion of the maxillary sinus, which usually arises from the maxillary antrum and causes bone remodelling due to mass effect. On CT the mass is of homogeneous low density reflecting the oedematous nature of the polyp. They fill the antrum, expanding through the secondary ostium into the ipsilateral nasal cavity and may even extend through the posterior choana into the nasopharynx. The oedematous mass displays low signal intensity on T1 weighting and high signal on T2. There may also be peripheral enhancement post gadolinium. By definition an antrochoanal polyp extends into the nasal cavity and the diagnosis is aided by the evidence of bony remodelling rather than erosion, the latter being suggestive of a malignant process. A mucocele can be expansile but would not extend beyond the cavity of the sinus. An inverted papilloma displays moderate enhancement on CT and intermediate signal intensity on T1W images with definite enhancement post contrast.

Question 29

10 A five-year-old boy presented with hearing loss. An intact, dry tympanic membrane was visualised and audiology confirmed a conductive hearing loss. A CT was performed which revealed a lesion medial to and eroding the ossicular chain which fills the oval window niche and does not enhance following contrast. An MRI confirmed the lesion was low intensity on Ti and high signal intensity on T2-weighted images. What is the most likely diagnosis?

a Acquired cholesteatoma

b Glomus tympanicum

C Cholesterol granuloma

d High jugular bulb

e Congenital cholesteatoma

Answer 29

10 Answer E: Congenital cholesteatoma

Cholesteatomas can be classed as either congenital or acquired. They appear as relatively wellcircumscribed masses, which sometimes contain cystic areas and do not enhance post contrast. A congenital cholesteatoma typically occurs in childhood as a result of inclusion of squamous epithelium within the temporal bone during development. An intact TM is visible on both examination and on radiological images and the patient is often asymptomatic. An acquired cholesteatoma arises from a retraction pocket of the tympanic membrane, usually causing a chronically discharging ear and grossly abnormal tympanic membrane. In 70-80 % of cases of acquired cholesteatoma the mass is seen lateral to the ossicular chain. Conversely, in the congenital form it is medial and fills the oval window niche. Cholesterol granulomas are granulomatous lesions, which are thought to arise as a result of an inflammatory process, and contain both cholesterol and haemosiderin deposits. The appearances on CT are very similar to those of cholesteatomas and may even be indistinguishable. On MRI, however, cholesterol granulomas can be differentiated from congenital cholesteatomas. Cholesterol granulomas display high signal intensity on both Ti- and T2-weighted images as a result of the presence of haemoglobin breakdown products. Cholesteatomas are of low signal intensity on Ti and high intensity on T2W images. Glomus tympanicum are a type of paraganglioma arising from the paraganglion cells around Jacobson’s nerve in the middle ear. They are the most common primary neoplasms of the middle ear and on examination can be seen as a pulsating cherry red mass behind the tympanic membrane. On CT the mass can be seen arising from the wall of the middle ear and as a result of its hypervascular nature displays intense enhancement post contrast on both MRI and CT.

Question 30

11 A 15-year-old girl complained of a six-month history of left-sided unilateral tinnitus. A pulsatile mass was visible in the ipsilateral middle ear. A high-resolution CT scan of the temporal bone showed an absent foramen spinosum with the internal carotid artery following an aberrant course laterally in the middle ear on this side. A carotid angiogram revealed a vascular structure arising from the aberrant carotid artery terminating in the middle meningeal artery. What is the most likely diagnosis?

a Persistent stapedial artery

b Glomus jugulare tumour

C High jugular bulb

d Middle ear paraganglioma

e Glomus tympanicum

Answer 30

11 Answer A: Persistent stapedial artery

A persistent stapedial artery (PSA) is a vascular anomaly that arises from the pertons part of the internal carotid artery. It can present with hearing loss, pulsatile tinnitus or a mass seen over the promontory in the middle ear on otoscopic examination but is often an incidental finding. The prevalence is approximately 0.05%. The stapedial artery develops from the hyoid artery during early foetal life and divides into upper and lower branches. The upper branch becomes the middle meningeal artery and the lower leaves the cranial cavity via the foramen spinosum and becomes the inferior alveolar and infraorbital arteries. If the stapedial artery persists then the middle meningeal artery arises from it and the foramen spinosum is aplastic, hence absence of the foramen spinosum is an indirect sign of PSA. A small vessel arising from the petrous part of the internal carotid artery and coursing through the middle ear cavity may be visible on CT and if not recognised, injury can cause haemorrhage during middle ear surgery. PSA can also be associated with an aberrant internal carotid artery.

Question 31

14 A patient presents to the ophthalmologist with proptosis and bossing of the forehead. A CT scan shows complete opacification of the frontal sinus with bony expansion and remodelling. On MRI there is opacification of the frontal sinus with peripheral rim enhancement. What is the most likely diagnosis?

a Mucous retention cyst

b Frontal sinus mucocele

c Inverted papilloma

d Sinusitis

e Frontal sinus squamous cell carcinoma

Answer 31

14 Answer B. Frontal sinus mucocele

A sinus mucocele is an expansile lesion, which develops as a result of obstruction of the sinus ostium, containing mucoid secretions and lined by respiratory epithelium. Mucoceles can arise from any of the sinuses but most commonly affect the frontal sinus (65% of cases) with the sphenoid being the least affected. On CT scan there is complete opacification of the sinus as it is filled with mucoid secretions causing the sinus cavity to enlarge and the walls to undergo remodelling and thinning due to pressure necrosis. The diagnosis is confirmed if there is complete absence of any remaining air within the sinus. These appearances are in contrast to mucous retention cysts, which occur because of blockage and swelling of a mucous gland within the sinus mucosa and therefore air remains within the sinus cavity itself. Characteristic appearances on CT are that of an expanded frontal sinus cavity filled with homogeneous low-attenuation matter. The peripheral rim enhancement enables it to be differentiated from other pathologies such as inverted papilloma. Due to the high water content (>95%) of the secretions the signal intensity on MR is of low intensity on Ti and high on T2W images. A malignant pathological process would be expected to cause bone destruction as opposed to remodelling. A frontal mucocele can extend into the upper orbit causing the patient to experience a range of symptoms such as proptosis, nasal obstruction and bossing of the forehead.

Question 32

15 An elderly diabetic patient presented to his GP with severe right ear pain out of keeping with the visible findings of an erythematous external auditory canal with some granulation tissue. A CT scan was performed and an abnormal soft-tissue mass was visualised in the eternal auditory canal. He was subsequently diagnosed with malignant otitis externa. Which of the following is the most appropriate?

a On MRI the granulation tissue would be expected to be low intensity on both Ti- and T2- weighted images

b CT is the imaging modality of choice to assess skull base involvement

C The radiological appearances are usually contemporaneous with the clinical findings

d SPECT is ineffective in monitoring for disease progression and post therapeutic recurrence

e Sclerosis of the mastoid and temporal bones is a characteristic feature of malignant otitis externa on CT

Answer 32

15 Answer A: On MRI the granulation tissue would be expected to be low intensity on both Ti- and T2-weighted images

Malignant otitis externa is a potentially fatal infection of the external ear, which presents with severe, deep otalgia and tends to affect immunocompromised individuals, particularly those with diabetes. It is almost always associated with pseudornonas aeruginosa. A high index of suspicion is required and if left undiagnosed the infection can result in osteomyelitis of the skull base causing erosion of the mastoid and temporal bones. This can result in lower cranial nerve palsies, sigmoid sinus thrombosis as well as meningeal and intracranial involvement. On CT an abnormal soft-tissue mass is visualized in the external auditory canal with associated bony destruction and opacification of the mastoid air cells. On MRI the granulation tissue is classically low intensity on both T1- and T2-weighted images. MRI is generally superior to CT with regard to detection of skull base involvement due to its ability to identify bone marrow oedema. The radiological appearances usually lag behind the clinical andpathological findings.

Question 33

20 A 55-year-old female presents with a right-sided facial weakness, hyperacusis, loss of lacrimation and taste. What pathology is most likely to cause this pattern of clinical findings?

a Facial nerve schwannoma

b Acoustic neuroma

C Brain stem glioma

d Parotid malignancy

e Malignant otitis media

Answer 33

20 Answer A: Facial nerve schwannoma

The intratemporal segment of the facial nerve is affected in this case. A facial nerve schwannoma is the only lesion that can be limited to this region. Acoustic neuromas can involve CN VIII while brain stem gliomas are likely to involve other cranial nerves, such as VI. Parotid malignancy and malignant otitis media could compromise the extracranial parotid segment of the facial nerve but would not be expected to be associated with the loss of lacrimation and taste.

Question 34

12 A two-year-old boy presented with a discharging mass on the bridge of the nose, which did not heal despite a prolonged course of broad-spectrum antibiotic therapy. Prior to biopsy, imaging was performed. An MRI scan confirmed a cystic lesion, which was of heterogeneous increased signal on T1 W and T2 imaging. The density of the lesion on CT was that of fat. What is the most likely diagnosis?

a Encephalocele

b Dermoid cyst

C Nasal glioma

d Sebaceous cyst

e Potts puffy tumour

Answer 34

12 Answer B: Dermoid cyst

Dermoid cysts usually occur along the midline and are commonly found at this location. They are thought to occur within the region where the neural tube closes. A nasal dermoid cyst can be associated with a deep sinus with potential communication with the intracranial cavity. Dermoid cysts contain skin and sebaceous material, giving them a density similar to fat on CT. On MRI they display high signal intensity on T1W images and are hyperintense on T2. An encephalocele also usually arises in the midline but more than 90% occur posteriorly in the region of the occiput and they are associated with a defect in the skull table allowing herniation of meninges, brain parenchyma and CSE Potts puffy tumour can occur as a complication of frontal sinusitis and consists of osteomyelitis of the frontal bone, which can progress to an extradural abscess.

Question 35

13 A 33-year-old male presented with a history of gradually worsening unilateral nasal obstruction and epistaxis. Endoscopy revealed a polypoidal mass filling the left nasal cavity. CT scan showed a soft-tissue mass arising from the lateral nasal wall with associated bone destruction of the medial wall of the maxillary sinus and heterogeneous enhancement post administration of contrast. An MRI scan confirmed intermediate signal intensity on both Ti and T2W images with avid enhancement post administration of gadolinium. What is the most likely diagnosis?

a Mucocele of ethmoidal sinus

b Inverted papilloma

C Mucous retention cyst

d Nasopharyngeal carcinoma

e Nasal polyp

Answer 35

13 Answer B: Inverted papilloma

Inverted papillomas arise from the lateral nasal wall and appear macroscopically similar to nasal polyps but with frond-like projections. The underlying respiratory epithelium exhibits an endophytic growth pattern. Even though these are benign lesions there is a possibility of focal malignant transformation and therefore regular surveillance is usually undertaken. The avid enhancement post contrast differentiates an inverted papilloma from a mucocele. Nasal polyps, mucoceles or mucous retention cysts would not be expected to exhibit bony destruction.

Question 36

15 A patient presents with acute onset headache, right-sided otorrhoea and associated abducent nerve palsy. CT revealed opacification of the petrous apex on the symptomatic side and cavernous sinus enhancement. On MRI there was a low signal mass within the petrous apex, which demonstrated bright peripheral enhancement with contrast. The mass was hyperintense on T2W. What syndrome is this patient suffering from?

a Gradenigo’s syndrome

b Korsakoff’s syndrome

C Chilaiditi’s syndrome

d Riley-Day syndrome

e Gerstmann’s syndrome

Answer 36

15 Answer A: Gradenigo’s syndrome

This patient has developed an abscess in the aerated petrous apex, which typically spreads from the middle ear. The infected phlegm irritates the fifth and sixth nerves as they pass the petrous apex causing the triad of symptoms called Gradenigo’s syndrome (otitis media, retro-orbital pain and a sixth nerve palsy). Typically, infective agents are pseudomonas and enterococcus. The petrous apex is aerated in approximately 30% of the population. Korsakoff’s syndrome is typically seen in alcoholics with thiamine deficiencies that have an inability to produce new memories, and confabulate. Riley- Day syndrome is an inherited condition resulting in dysautonomia. Gerstmann’s syndrome is characterised by four primary symptoms of dysgraphia, dyscalculia, finger agnosia and left to right disorientation. Chilaiditi’s $ describes interposition of colon between the liver and the diaphragm

Question 37

16 A 16-year-old male presented with epistaxis following contact sports. CT revealed a large mass in the nasopharynx extending into the pterygopalatine and infratemporal fossa. Following contrast, there was significant enhancement and erosion of the medial pterygoid plate was seen. What treatment would be an appropriate next step in his management?

a Conservative management

b Medical management

c Embolisation

d Direct intratumoral alcohol injection

e Surgical excision

Answer 37

16 Answer C: Embolisation

Given the presentation and radiological features the mass is most likely to be a juvenile angiofibroma. These tumours typically arise from the region of the sphenopalatine foramen and extend into the pterygopalatine and infratemporal fossa. On CT there is characteristic erosion of the medial pterygoid plate, which is a useful distinguishing feature between juvenile angiofibromas and other nasopharyngeal mass lesions. Angiography is not necessary for diagnostic purposes, but may be carried out prior to pre-operative embolisation. Therapeutic embolisation is an adjunct to surgery as the whole supply to the tumour cannot generally be embolised.

Question 38

19 A 30-year-old man presents with bilateral external ear masses. Otoscopic examination reveals these lesions to be a build up of layers of flaky skin. Further history elucidates chronic sinusitis and bronchiectasis. What is the most likely diagnosis?

a Keratosis obturans

b Van der Hoeve syndrome

C Malignant otitis externa

d Surfer’s ear

e Cholesteatoma

Answer 38

19 Answer A: Keratosis obturans

Keratosis obturans is a bilateral process of inflammatory ear masses in association with chronic sinusitis and bronchiectasis. Van der Hoeve syndrome is characterised by osteogenesis imperfecta and osteosclerosis. Malignant otitis externa, surfer’s ear and cholesteatoma could all account for inflammatory external ear masses but have no other clinical associations.

Question 39

41 Following a high-speed RTA a 45-year-old male had a multitrauma scan. A fracture was seen running across the right petrous temporal bone extending from the squamous portion laterally to the mesotympanum medially. Opacification of the mastoid air cells was evident. What is the patient most at risk of?

a Sensorineural deafness

b Ossicular dislocation

c Irreversible facial paralysis

d CSF rhinorrhea

e Recurrent mastoiditis

Answer 39

41 Answer B: Ossicular dislocation

The fracture described is a longitudinal fracture of the petrous temporal bone, which runs parallel to the axis of the bone. Ossicular dislocation, most commonly incudostapedial, is usually present. Facial paralysis occurs in 10-20% secondary to oedema but resolves spontaneously. Otorrhoea may be seen. In transverse fractures, which run perpendicular to the axis of the pyramid, there is irreversible sensorineural hearing loss & facial paralysis in 50%.

Question 40

22 A 35-year-old pregnant female with a family history of deafness presented with accelerated hearing loss. Otological examination was unremarkable and audiological assessment confirmed a mixed hearing loss primarily affecting the higher frequencies. A working diagnosis of cochlear otosclerosis was postulated. What classical finding would you expect to see on CT?

a A ring of low density around the cochlea

b Hypersclerosis of a poorly pneumatised mastoid

c Ossification of the oval window

d Hypodense opacity of the mesotympanum without bony erosion

e Ossicular destruction and bony scalloping

Answer 40

22 Answer A: A ring of low density around the cochlea

The double ring sign is due to demineralisation of the surrounding bone and is a classical finding in cochlear otosclerosis. Hypersclerosis of a poorly pneumatised mastoid is most likely to represent mastoiditis, while ossification of the oval window would support a diagnosis of fenestral sclerosis. Hypodense opacity of the mesotympanum without bony erosion is suggestive of chronic otitis media, while ossicular destruction and bony scalloping could represent cholesteatoma.

Question 41

24 A 40-year-old patient has unilateral pulsatile tinnitus. Audiometry reveals a conductive hearing loss on that side, otoscopy shows a vascular retrotym- panic mass lying behind the inferior tympanic membrane and CT reveals a tubular mass crossing the middle ear cavity from posterior to anterior with no associated bone changes, although there is an enlarged inferior tympanic canaliculus. What is the most likely diagnosis?

a Aberrant internal carotid artery

b Dehiscent jugular bulb

C Glomus tympanicum

d Glomus jugulotympanicum

e Cholesterol granuloma

Answer 41

24 Answer A: Aberrant internal carotid artery

The most important feature on CT imaging is whether the lesion is of a tubular nature. This would steer you away from a diagnosis of glomus tympanicum and should prevent you a dangerous biopsy. A glomus tumour would show permeative bone changes and a dehiscent jugular bulb would also most likely show focal absence of the jugular plate.

Question 42

14. A 49-year-old presents with a history of painless discharge, hearing loss and fullness in the left ear. CT shows a soft tissue mass in the middle ear with intact jugular fossa. Coronal reconstructions show erosion of the epitympanic ossicular chain with intact scutum. MRI shows that the soft tissue mass is hypointense on T1 and intermediate signal on T2 with no enhancement with gadolinium. The most likely diagnosis is?

(a) Secondary cholesteatoma

(b) Chronic otitis media

(c) Granulation tissue

(d) Squamous cell carcinoma

(e) Acute otitis media

Answer 42

14. (a) Secondary cholesteatoma

Definitive diagnosis of cholesteatoma requires CT evidence of bone erosion, either of the ossicular chain or the walls of tympanic cavity. Pars tensa cholesteatoma typically spares the scutum and results in lateral displacement of the head of the malleus and the incus. Granulation tissue shows high signal on T2 and enhances with gadolinium. Squamous cell carcinoma also shows contrast enhancement.

Question 43

17. A 20-year-old man presents with swelling around his left eye. A CT scan shows a high attenuation mass lesion which expands the ethmoid air cells with bony erosion. There are small punctate calcifications seen within the mass. On MRI, the mass returns low signal on T1 and T2. The most likely diagnosis is?

(a) Fungal sinusitis

(b) Chronic sinonasal polyposis

(c) Nasopharyngeal carcinoma

(d) Juvenile angiofibroma

(e) Chronic sinusitis

Answer 43

17. (a) Fungal sinusitis

CT findings are typical, showing a hyperdense lesion with calcifications and bony erosion. The ethmoid sinus is most commonly involved and bony expansion with erosion is characteristic. On MRI, the lesion is low signal on T1 and T2 due to high fungal mycelial iron, magnesium and manganese from amino acid metabolis.

Question 44

18. A 15-year-old girl presents with symptoms of chronic sinusitis. CT of the paranasal sinuses shows a low density mass opacifying the right maxillary antrum and extending to the posterior choana. No bony destruction is seen. The left maxillary antrum also shows mucosal thickening. The most likely diagnosis is?

(a) Juvenile angiofibroma

(b) Antrochoanal polyp

(c) Fungal sinusitis

(d) Inverted papilloma

(e) Intranasal glioma

Answer 44

18. (b) Antrochoanal polyp

These are seen as low attenuating masses from the maxillary antrum extending through a sinus ostium to the choana. They show non-aggressive features with peripheral enhancement. MRI shows a hypo to variable signal on T1 with hyperintense on T2 with peripheral enhancement.
Juvenile angiofibroma is seen in adolescent males with an intensely enhancing mass extending to the posterior nasopharynx. Inverted papilloma are seen in older males as a locally aggressive mass of the middle meatus extending into maxillary sinus. Intranasal glioma present at birth as a very soft mass centred at the nasal dorsum.

Question 45

45. A 45-year-old man presents with deafness and left ear discharge. CT of the petrous and mastoids shows a soft tissue mass in the attic with erosion of the scutum. No contrast enhancement is seen. What is the most likely diagnosis?

(a) Glomus tympanicum

(b) Pars tensa cholesteatoma

(c) Pars flaccida cholesteatoma

(d) Cholesterol granuloma

(e) Congenital cholesteatoma

Answer 45

45. (c) Pars flaccida cholesteatoma

This typically causes erosion of the scutum, ossicles or the lateral epitympanic wall. Pars flaccida is a small superior portion of the tympanic membrane. Scutum erosion is common and three-quarters of cases may have erosion of the ear ossicles.

Question 46

46. A 52-year-old woman presents with hearing loss in the right ear. Examination reveals a non-pulsating, bluish discoloration of the ear drum. CT shows a smooth expansile mass lesion in the middle ear which bulges the tympanic membrane laterally. On MRI, the lesion returns high signal on T1 and T2 sequences. What is the most likely diagnosis?

(a) Cholesterol granuloma

(b) Chronic otitis media

(c) Glomus jugulare

(d) Cholesteatoma

(e) Haemorrhagic otitis media

Answer 46

46. (a) Cholesterol granuloma

This is caused by recurrent haemorrhage into the middle ear cavity forming an inflammatory mass of granulation tissue. Diagnosis is made by demonstration of bony expansion on CT and high signal on T1 and T2

Question 47

49. A 9-year-old boy presents with chronic right facial pain. Radiography shows an opaque right maxillary antrum. A CT scan of the paranasal sinuses shows that the right maxillary antrum is filled with soft tissue with destruction of med and post bony walls. No significant sinus mucosal disease is seen in other paranasal sinuses.
    What is the most likely diagnosis?

(a) Fungal infection

(b) Allergic sinusitis

(c) Rhabdomyosarcoma

(d) Antrochoanal polyp

(e) Acute sinusitis

Answer 47

49. (c) Rhabdomyosarcoma

Bone destruction suggests an aggressive lesion at this site and rhabdomyosarcoma would be the most likely diagnosis in a young person.

Question 48

50. A 40-year-old migrant worker of Chinese origin presents with a chronic history of nasal congestion and recent epistaxis. CT of the paranasal sinuses shows a large soft tissue mass in the post-nasal space. There is also bony destruction with erosion of the basisphenoid. What is the most likely diagnosis?

(a) Chronic polyposis

(b) Juvenile angiofibroma

(c) Nasopharyngeal carcinoma

(d) Fungal infection

(e) Pharyngeal abscess

Answer 48

50. (c) Nasopharyngeal carcinoma

The lesion is aggressive with bony destruction and is likely to be malignant. Nasopharyngeal carcinomas have a high incidence in the Chinese population. It can feature bony destruction of the basisphenoid, basiocciput or the petrous tip. There may also be cranial nerve involvement, either at their exit through the foramina or secondary to intracranial extension.

Question 49

9. Which of the following statements are correct about Congenital cholesteatoma of the middle ear: (T/F)

(a) 80 % of middle ear cholesteatoma are congenital in origin

(b) Facial nerve palsy is a recognized complication.

(c) The anterosuperior aspect of the middle ear is a typical location.

(d) MRI is the imaging modality of choice.

(e) Is associated with poorly pneumatised mastoid air cells:

Answer 49

Answers:

(a) Not correct
(b) Correct
(c) Correct
(d) Not correct
(e) Not correct

Explanation:

Congenital cholesteatoma accounts for 2% of all cholesteatomas and are clinically differentiated from acquired as they occur behind an intact tympanic membrane in patients without a history of tympanic perforation or otorrhoea. CT provides more accurate information regarding the mass and bony structures than MRI. Well pneumatised mastoid air cells are seen in congenital cholesteatomas than in acquired.

Question 50

(Ped) 25. Which of the following statements are correct about Juvenile angiofibromas: (T/F)

(a) Biopsy is contraindicated.

(b) Almost exclusively affects females.

(c) Widening of the pterygopalatine fossa is only seen in advanced cases.

(d) Is the commonest benign nasopharyngeal tumour.

(e) Invasion of the sphenoid sinus occurs in up to two thirds of cases

Answer 50

Answers:

(a) Correct
(b) Not correct
(c) Not correct
(d) Correct
(e) Correct

Explanation:

Juvenile angiofibromas affects only males. Widening of pterygopalatine fossa is seen in 90% of the cases. Due to significant vascularity and the risk of haemorrhage, biopsy is always contraindicated.