|Year : 2013 | Volume
| Issue : 2 | Page : 88-91
Primary external auditory canal cholesteatoma presenting as cerebellar abscess
Sanjeev Bhagat1, Saurabh Varshney2, Sampan Singh Bist1, Sarita Mishra1, Namita Kabdwal1, Ranjeet Kumar1
1 Department of ENT and Neurosurgery, Himalayan Institute of Medical Sciences, Swami Ram Nagar, Doiwala, Dehradun, India
2 Department of ENT, All India Institute of Medical Sciences, Rishikesh, India
|Date of Web Publication||15-Jun-2013|
Professor - Otorhinolaryngology (ENT), All India Institute of Medical Sciences (A.I.I.M.S.), Virbhadra Road, Rishikesh- 249201, Dehradun (Uttarakhand)
Source of Support: None, Conflict of Interest: None
External auditory canal cholesteatoma (EACC) is an uncommon disease and its pathogenesis remains unclear. Clinically, patients usually present with symptoms like chronic dull pain and otorrhea, but many patients can be astonishingly silent or even asymptomatic. The intracranial complication with extensive mastoid cavity from primary EACC is extremely rare. Early diagnosis is imperative to facilitate best possible intervention and to relieve patient symptoms and to prevent further complications. We present the first report in the English literature of a case of primary EACC presenting as cerebellar abscess. We experienced a rare case of a 55-year-old female patient admitted in our hospital with cerebellar abscess complicated by a cholesteatoma in the external auditory canal. The patient was first managed conservatively with systemic antibiotics by neurosurgeon, and then the disease was removed successfully by canal wall down mastoidectomy and no recurrence had occurred in the first 4 months post-operatively.
Keywords: Cerebellar abscess, Complications, External auditory canal choleasteatoma
|How to cite this article:|
Bhagat S, Varshney S, Bist SS, Mishra S, Kabdwal N, Kumar R. Primary external auditory canal cholesteatoma presenting as cerebellar abscess. Indian J Otol 2013;19:88-91
|How to cite this URL:|
Bhagat S, Varshney S, Bist SS, Mishra S, Kabdwal N, Kumar R. Primary external auditory canal cholesteatoma presenting as cerebellar abscess. Indian J Otol [serial online] 2013 [cited 2020 Apr 9];19:88-91. Available from: http://www.indianjotol.org/text.asp?2013/19/2/88/113515
| Introduction|| |
External auditory canal cholesteatoma (EACC) is a rare disease with an estimated incidence of 1 in 1000 new otological patients.  The disease is characterized by excessive accumulation of keratin material in the external auditory canal (EAC) as well as osteonecrosis with focal appearance of sequestrated bone lacking the epithelial covering.  The etiopathology of the EACC remains uncertain.
Clinically, symptoms like otorrhea with chronic dull pain are frequently reported, but many patients can be remarkably silent or even asymptomatic. , Hence, EACC may be a dangerous entity concealing serious destruction with few or no symptoms.
The reported complications of EACC with extensive mastoid cavity involvement includes facial nerve paralysis, ossicular erosion, and labyrinthine fistula. ,, Imaging is helpful to define the extent of the lesion and delineate its proximity to middle ear and neurovascular structures. 
Here, we present a rare case of primary EACC with extensive involvement of mastoid cavity and subsequently invading the posterior fossa dura and presenting as cerebellar abscess. The patient was first managed conservatively by neurosurgeon, and then the disease was removed successfully by canal wall down mastoidectomy.
To the best of our knowledge, there has been no previously reported case in the English literature of EACC presenting with intracranial complication. We present this case with clinical and radiological finding along with management of such a case.
| Case Report|| |
A 55-year-old female admitted in the neurosurgery department with a history of intermittent fever and headache on left side for 1 month. On physical examination, patient was febrile, and in altered sensorium with Glassgow Coma Scale (E3 M6 V4). contrast enhanced computerized tomography (CECT) brain showed well-defined hypo dense space occupying lesion with irregular rim enhancement and perifocal edema of surrounding tissue, suggestive of abscess in left cerebellar hemisphere [Figure 1]. Imaging also revealed large soft-tissue mass eroding the posterior EAC wall [Figure 2]. The patient was managed conservatively with systemic antibiotics. ENT reference was sent to rule out otogenic cause for cerebellar abscess. Besides the above presenting complaints, patient also had history of otorrhea and otalgia in her left ear for 1 month along with vertigo and tinnitus, but did not complaint of hearing loss. No history of previous ear disease, significant trauma, or surgery was present. Otoendoscopic examination revealed erosion of posterior wall of left EAC with presence of keratin debris and with normal tympanic membrane [Figure 3]. Bilateral facial nerve was intact. X-ray mastoid (schuller view) showed large lytic area in the mastoid region [Figure 4]. Pure tone audiogram was normal in both the ears.
|Figure 1: CECT brain showing well defined hypo dense space occupying lesion with irregular rim enhancement and perifocal edema of surrounding tissue, suggestive of abscess in left cerebellar hemisphere|
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|Figure 2: CT imaging showing large soft-tissue mass eroding the left posterior external auditory canal wall|
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|Figure 3: Otoendoscopic picture showing erosion of posterior wall of left external auditory canal with presence of keratin debris and with normal tympanic membrane|
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|Figure 4: X-ray mastoid (schuller view) showing large lytic area in the mastoid region|
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After clearance from neurosurgeon the patient was taken up for surgery. A post-auricular approach was used to expose the disease in the EAC. Large defect in the posterior wall of EAC with extensive invasion into the mastoid air cells by keratin debris was noted. The ear drum was intact. Modified radical mastoidectomy was done with preservation of tympanic membrane and ossicles. The eroded region was occupied by the squamous debris and a cholesteatoma sac which was removed carefully till posterior fossa dura was reached. Small breach in the dura was seen. The temporalis fascia graft was used to line the exposed dura. Post-operative period was event free and the cavity healed well. Patient was discharged on 14 th day of surgery. Patient has been on regular follow-up for 3 months with well healed cavity and free from presenting symptoms.
| Discussion|| |
Cholesteatoma confined to the EAC is extremely uncommon and its pathogenesis remains unclear. EACC have been categorized into several types, including the rare primary or idiopathic type as well as secondary types related to EAC stenosis, chronic inflammation, trauma, post-surgical, and post-radiation causes. ,
There are many reported series describing secondary cases of EACC but only a few reports of primary unilateral cholesteatomas. , Our patient was a primary case, as there was no history of previous ear disease, significant trauma, or surgery. Suggested risk-factors for the development of primary EACC include disruption of the local microcirculation by microtrauma from use of cotton swabs, smoking, or diabetes mellitus. 
EACC occurs more frequently among the elderly despite cases being reported in children and young adults.  Clinically, patients with EACC usually presents with symptoms like chronic dull pain and otorrhea, but many patients can be amazingly silent or even asymptomatic. , Hearing loss is uncommon unless the cholesteatoma invades the middle ear or attic.
The diagnosis is based on history and physical examination. computed tomography (CT) imaging is helpful to delineate the extent of disease. EACC is most commonly seen as an EAC soft-tissue mass with associated bone erosion and intramural bone fragments on high-resolution temporal bone CT examination.  The EACC may extend into the mastoid and middle ear, or it may involve the facial nerve canal or tegmen tympani and later on presenting as complications. Recognition of this entity and its possible extension is important because it may influence clinical management. There are only a few reports describing cases of EACC with extensive invasion into the mastoid cavity. ,,,,
Vrabec and Chaljub reviewed 39 patients of EACC, and found a single case of pre-operative facial nerve dysfunction. 
Owen et al. retrospectively evaluated the clinical records of 48 patients of EACC. They found temporomandibular joint (TMJ) was exposed in 11 cases, while mastoid and middle ear was invaded in six and three cases, respectively. In one primary case the facial nerve was exposed and in a post-traumatic case the atticus and antrum were invaded. 
Naim et al. classified 17 patients of EACC by different histopathological and clinical findings into four stages, with Stage IV, representing destruction of adjacent structures, including the skull base, TMJ, mastoid and facial nerve. Only one patient presented in Stage IV, with erosion of the mastoid cells. 
Darr, and Linstrom reviewed ten cases of primary EACC. They reported erosion of mastoid air cells in seven patients, middle ear in six patients, TMJ in two, otic capsule in two, and Fallopian canal More Details in one patients. 
In our case, the extension of the disease in the temporal bone is unusual. After eroding the posterior EAC and mastoid cavity, the disease had involved the posterior fossa dura, and presented as cerebellar abscess, without involving the middle ear, TMJ, and facial nerve.
The intracranial complication with extensive mastoid cavity from primary EACC is extremely rare. Our case probably represents the first reported case of primary EACC with extensive mastoid involvement and presenting as cerebellar abscess. The most frequent pathway for EACC to spread to the brain is by means of cholesteatomatous bone erosion and formation of an extradural abscess.
The differential diagnosis includes keratosis obturans, necrotizing external otitis, and tumors. 
The management of EACC is debatable in terms of surgery versus conservative treatment. It has been recommended that all patients should undergo surgical removal of the cholesteatoma and necrotic bone to prevent progression and continued erosion.  Surgical treatment is recommended for EACC, especially in cases of chronic pain constant infection and complications (hypoacusis, facial paralysis, chronic vertigo, lesion progression, hypotympanum involvement, jugular foramen or mastoid involvement).  When the mastoid air cells are invaded, a modified radical mastoidectomy may be indicated, with the tympanic membrane and ossicles left intact. 
| Conclusion|| |
EACC may presents as an insidious entity concealing serious destruction with few or no symptoms. Endocranial abscess from primary EACC is extremely rare. Early diagnosis is paramount to enable optimal intervention and to relieve patient symptoms and prevent further complications. Aggressive surgical treatment is recommended when complications are present or imminent. With adequate surgical procedures, good outcomes can be achieved with good hearing.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]