Post-operative temporal lobe encephalocele

@#This 24-year-old woman presented to ENT outpatients with an enlarging swelling in the right external auditory canal. A radical mastoidectomy for chronic suppurative otitis media with cholesteatoma had previously been undertaken at another institution. On clinical examination there was an otologic mass that was tender on probing. High resolution imaging of the temporal bones and a subsequent MRI brain confirmed the mass was a temporal lobe encephalocele. A temporal lobe encephalocele is where a segment of the temporal lobe invaginates through a defect in the tegmen tympani. The brain is separated from the middle ear and mastoid process by an exceptionally thin layer of bone – the tegmen tympani. Damage to the tegmen compromises the barrier with the brain and may occur for a number of reasons. This includes congenital, traumatic, post-infectious, malignant invasion, post-radiation therapy and post-surgical causes.1 When this occurs the brain may extrude through the defect resulting in a temporal lobe encephalocele. A bony defect alone, whatever the cause, is insufficient to always result in an encephalocele. Even with dehiscence of the tegmen the dura is capable of supporting the brain issue without herniation. Only when the integrity of the dura is compromised does an encephalocele occur.2 This may be due to the underlying disease process (such as cholesteatoma causing an intracranial abscess) or both purposeful (opening dura to drain an adjacent intracranial abscess) /non-purposeful surgical intervention. Mainstream microsurgical techniques however have lowered the incidence of dural violation.3 Historically, infection was a major cause, but with the ready availability of antibiotics and prompt management, the key contemporary cause is iatrogenic, following mastoid surgery. However, the overall incidence is uncommon following otologic surgery. In a review of 25 years of middle ear/mastoid encephalocele cases 77% were identified to be iatrogenic in origin.4 This patient presented with the finding of a mass observed in the external auditory canal. Less common findings at attendance include tympanic perforation, cholesteatoma, otorrhoea and meningitis.4 The key to diagnosis hinges on cross-sectional imaging: combined imaging with CT to assess the osseous structures and MRI for soft tissue review. The high-resolution CT (HRCT) of the temporal bones illustrates a large defect in the right tegmen tympani with a large soft tissue lesion occupying the post-surgical mastoid cavity abutting the tympanic membrane. (Figures 1A, B) The defect of 15mm in the tegmen was more than double the average of 7.2mm reported elsewhere.4 The MRI confirms the defect in the tegmen with the protrusion of a knuckle of the right temporal lobe and its overlying meninges through the defect into the mastoid cavity. The dumb-bell appearance is typical with the narrower neck at the site of the tegmental dehiscence. The extruded brain occupies the post-operative middle ear cavity. (Figures 2 A, B and C) The defect size and volume of herniated brain can be accurately assessed, both of which may be key determinates of the type of surgical procedure. Revision mastoidectomy with repair of the tegmen defect and dural integrity using a combined intracranial-mastoid approach is planned as a joint case with neurosurgical colleagues.

Intracranial complications of acute sinusitis on brain CT

@#<p class="MsoNormal" style="text-indent: .5in;">This 35-year-old woman presented to a peripheral hospital Accident and Emergency department in a moribund state.  She was intubated, stabilized and transferred urgently to a tertiary centre. She had attended the hospital in the prior week with a diagnosis of sinusitis.</p><p class="MsoNormal" style="text-indent: .5in;">An urgent CT brain was requested by the attending A and E officer which was undertaken on the basis of her low Glasgow coma scale (GCS).   The paranasal sinuses were partially visualised on this investigation.</p><p class="MsoNormal" style="text-indent: .5in;">Acute bacterial rhinosinusitis is a common disease presenting to both general practitioners and ENT surgeons.  It is on the most part short-lived in duration responding to antibiotics and symptomatic medications.  Rarely it may be associated with severe life threatening complications, in the form of intra-orbital extension or even less so intracranial complications. These typically occur in the pediatric and young adult population.1</p><p class="MsoNormal" style="text-indent: .5in;">Cross-sectional imaging plays an essential role in the assessment of this small sub-set of patients and is largely and almost always in the first instance with CT.2 Computed Tomography is broadly available, even out of standard working hours, and facilitates the review of potential intracranial complications and thereby guide neurosurgical management. Given that a proportion of the paranasal sinuses are always visualised on a CT brain it is an important review area, especially in patients with sepsis. </p><p class="MsoNormal" style="text-indent: .5in;">There are a number of well recognized intracranial complications of acute rhinosinusitis which include; meningitis, cerebral abscess, subdural empyema, cavernous sinus and dural venous thrombosis.3    Additional sequelae from the intracranial infection may result, such as arterial territory cerebral infarction, ventriculitis and hydrocephalus.  </p><p class="MsoNormal" style="text-indent: .5in;">Those patients in whom intracranial extension occurs often demonstrate bony destruction of the sinuses on imaging. Disease involving the frontal sinus is typically associated with intracranial complications, through foci of bony dehiscence or osteomyelitis involving the floor of the anterior cranial fossa.3  </p><p class="MsoNormal" style="text-indent: .5in;">In this case the patient presented in a moribund state due to severe intracranial complications following failed treatment in the community.  The initial CT imaging identified subdural collections (Figure 1a and 1b) as well as pan-sinusitis (Figure 2) and the suggestion of an arterial territory infarct (Figure 1a).  The frontal sinus however was not involved in this instance. </p><p class="MsoNormal" style="text-indent: .5in;">A complete CT study of the paranasal sinuses (with a dedicated paranasal sinuses protocol) is merited including isotropic reconstructions to review the bony integrity and aid the planning of ENT surgical intervention.  An MRI brain if available would eloquently confirm the CT findings including confirmation of the acute parietal lobe infarct.4</p><p class="MsoNormal" style="text-indent: .5in;">Neurosurgical drainage of the subdural empyemas was undertaken. Furthermore, functional endoscopic sinus surgery (FESS) was also performed with drainage of a large volume of pus from the sphenoid, ethmoidal and right maxillary sinuses.4</p><p class="MsoNormal" style="text-indent: .5in;">This case demonstrates intracranial complications are not an entity unique to the paediatric population.  When caring for patients with acute sinusitis always have a high index of suspicion for these potential complications and have a low threshold for engagement with radiology colleagues for imaging if concerned.   </p>

Olfactory neuroblastoma

@#This 57 year-old woman presented with a seizure. She had a history of attending the ENT and neurosurgical departments for more than a decade. At the time of her initial presentation many years prior, her main complaint was of nasal congestion. A nasopharyngeal biopsy confirmed an olfactory neuroblastoma. Olfactory neuroblastoma is an uncommon slow growing tumour of the nasal cavity with no established etiological basis. With a neuroectodermal origin, it arises from the olfactory epithelium of the upper nasal cavity.1 Most cases arise from the cribriform plate, upper third of the nasal septum, superior turbinates or anterior ethmoidal air cells. However, it typically presents late when multiple structures are involved, which may include the orbits and intracranial compartments.2 Accounting for approximately 2% of sinonasal tumors, although often late to present, ironically only a minority of patients experience anosmia.3 The commonest complaint at initial presentation is nasal blockage accounting for nearly a quarter of cases, with headache and epistaxis the next most frequent symptoms.1 Multi-modality imaging is essential in that the most recognized management of this infrequent tumor is a combination of craniofacial surgery and radiotherapy. The imaging pathway in this case was typical, with CT and MRI complementing each other in maximizing tumor delineation. Computed Tomography has superior definition is reviewing bony involvement which is a typical finding, whereas MRI has superiority in evaluating the extent of soft tissue invasion and establishing tumor boundaries against post obstruction fluid in the paranasal sinuses.3 In this case the CT illustrates the gross destruction of the skull base, orbital and sinus margins. (Figure 1-4) The MRI outlines the extension of disease involving the pituitary fossa, brainstem and frontal sinus invasion. (Figures 5 and 6)

Facial palsy and mastoiditis from fibrous dysplasia

@#This young adult man presented to ENT clinic with a complaint of left facial weakness and persistent left retro-auricular pain. High resolution CT of the mastoids was performed following clinical assessment. In this case, there is extensive sclerotic bony expansion with a ground-glass appearance involving the left zygoma, sphenoid and petrous temporal bone. The bony expansion is centred on the medullary bone and has an abrupt zonal transition (Figure 1). The bone involvement encompasses almost complete bony stenosis of the left external auditory meatus down to 1-2mm with consequential fluid in the external auditory canal and middle ears (Figure 2). The bony expansion involves both the tympanic and mastoid segments of the facial canal which are stenosed. The ossicular chain remains intact. The left mastoid air cells are under-pneumatised and completely occupied by fluid.

3D stereolithographic modeling of an inverted papilloma

@#This middle-aged woman presented for the first time to ENT clinic with a complaint of nasal stuffiness. Computed Tomography (CT) of the paranasal sinuses was performed following clinical review that revealed a left intranasal mass. Due to a radiological suspicion of an inverted papilloma, Magnetic Resonance Imaging (MRI) of the paranasal sinuses was performed. This, combined with endoscopic biopsy confirmed an inverted papilloma. Following referral to oral maxillofacial surgery (OMF), 3D modelling was performed using the original CT data to aid surgical planning.

Sensorineural hearing loss: What lies beneath? Neurovascular conflict secondary to a dural arteriovenous malformation

@#This middle-aged gentleman with no previous medical history presented to the local ENT outpatient clinic complaining of right-sided hearing loss. No history of trauma or previous head and neck surgery was elicited. Following clinical and auditory assessment a right sensorineural hearing loss was confirmed. A right-sided facial palsy was additionally identified on examination. A MRI of the internal auditory meati was performed (Figure 1a & 1b). Following radiologist review, MRI and MRA of the brain was undertaken.

Pyriform sinus fistula

@#This 17-year-old young man attended the oromaxillofacial (OMF) department of a tertiary surgical center. He had attended both local and overseas ENT departments since the age of 5 years. Previous, but unspecified surgery had been performed as a child, with ongoing problems, since with a discharging sinus on the anterior aspect of the lower left side of the neck. On clinical examination, several scars were present on the anterior aspect of the neck, and a skin opening was evident in the left para-midline of the lower neck. Following clinico-radiological discussion a barium swallow was undertaken (Figures 1 and 2).

CT 3D reformatting technique to aid microtia reconstruction procedure planning

@#This 8-year-old girl presented to a tertiary surgical centre with a history from birth of an absent left and a malformed right pinna, and associated bilateral hearing impairment. On clinical examination, the left pinna was absent and the right dysplastic. No penetrable external auditory meati were evident. Bilateral hearing impairment, more pronounced on the left, was confirmed with auditory testing.Prior to surgery high resolution CT imaging of the temporal bones was performed. In addition a CT of the lower thoracic cavity was undertaken to assess the costal cartilage for surgical planning.

Cerebral abscess with rupture into the ventricles due to chronic otitis media

@#This 43-year-old man with a known history of schizophrenia presented with a one-week history of left ear pain accompanied by a purulent discharge from the external auditory canal over the last 3 days. Shortly afterwards he became confused. On direct examination, the left ear canal was oedematous containing granulation tissue. This 43-year-old man with a known history of schizophrenia presented with a one-week history of left ear pain accompanied by a purulent discharge from the external auditory canal over the last 3 days. Shortly afterwards he became confused. On direct examination, the left ear canal was oedematous containing granulation tissue.

Signet ring cell lymphoma of the small bowel: a case report

Gastrointestinal lymphoma of the bowel is uncommon compared to adenocarcinoma. Signet ring cell lymphoma [SRCL] is a rare variant of non-Hodgkin's lymphoma that is characterized by clear cytoplasm with displaced nuclei to the periphery giving a signet ring appearance. Small bowel involvement has not been previously reported. We report the rare case of a 78-year-old female who presented with short history of fever, loss of appetite, nausea, vomiting, mild weight loss with abdominal discomfort and was later diagnosed to have SRCL of the ileum

Nasopharyngeal carcinoma presenting as a dual territory stroke: The hyperdense artery sign

@#This 63 year-old chinese female, with both diabetes and hypertension, underwent CT imaging of the brain after presenting with a progressive left sided hemiplegia. The ‘hyperdense artery sign’ is a generic description that can be evident in any artery of the body on unenhanced CT, occurring due to the presence of intraluminal thrombosis (Figure 1). It is a well-established sign, most commonly described in CT imaging of the brain, where it is visualised in the vast majority of cases in the middle cerebral artery in the context of an acute cerebral infarction.1 It occurs uncommonly elsewhere, with the internal carotid artery (ICA) and basilar artery being other clinically significant sites. The ‘hyperdense ICA’ sign has been reported to be a reliable and highly specific marker of thromboembolic occlusion of the internal carotid artery.2 The ‘hyperdense artery sign’ is related to the attenuation value of intraluminal thrombus. The CT attenuation value (Hounsfield unit or HU) of normal blood is dependent on the haematocrit, ranging from 20 to 30 HU. As the process of thrombus retraction occurs, its water content decreases, increasing the concentration of haemoglobin within the clot. As a result this raises the attenuation value of the thrombus to 50–80 H. So the term ‘hyperdense’ is given.3 In this case, it proved to be the presenting symptom for an undiagnosed nasopharyngeal tumour, the thrombus likely developing as a complication of the surrounding tumour within the nasopharyngeal recess. The resultant outcome was a dual territory cerebral infarction of the anterior and middle cerebral artery territories, both supplied by branches of the internal carotid artery (Figures 2a & 2b).

Complete dislocation of the lens of the eye - Always review the complete study

@#This 37 year-old male patient underwent high resolution CT imaging of the face including paranasal sinuses following trauma. Computed tomography (CT) has a well-established role in the assessment of the facial bones in the context of trauma, in particular for fractures involving the paranasal sinuses and orbit. High resolution imaging permits isotropic reconstruction in multiple planes. Its use in imaging the contents of orbit itself is more select, with both direct clinical examination and even orbital ultrasound used to assess the globe and lens of the eye.1 Traumatic dislocation of the lens of the eye may entail the partial or complete translocation of the lens from its normal position within the anterior aspect of the eye.2 The high attenuation lens ‘floats’, within the vitreous of the globe (Figures 1, 2 and 3). Following trauma to the face the injuries may be multiple and cross sub-speciality boundaries, but one should be alert to all injuries. In reviewing CT images one should be forensic in the review of all the anatomy covered, even it is not related to the original clinical query or not pertinent to one’s own clinical speciality. As an old mentor once told me, ‘Before you take the film down, have one last paranoid look.’ Learning Point: Always review the entirety of the imaging performed despite the focus of one’s clinical or speciality interest.