|Year : 2012 | Volume
| Issue : 1 | Page : 30-33
Invasive aspergillosis of the temporal bone
Renuka A Bradoo, Kshitij D Shah, H Gayathri, Mustafa A Kapadia
Department of E.N.T., Lokmanya Tilak Municipal Medical College and Hospital, Sion, Mumbai, Maharashtra, India
|Date of Web Publication||10-Jul-2012|
Kshitij D Shah
501, Diwani Mahal, Gulmohur Road No. 1, JVPD Scheme, Andheri (W), Mumbai - 400 049, Maharashtra
Source of Support: None, Conflict of Interest: None
Invasive aspergillosis of temporal bone, an extremely rare yet potentially life-threatening disease entity, occurs mostly in immuno-compromised individuals. We report a case of a 65-year-old diabetic male who presented with bilateral ear discharge, bilateral subepithelial ear masses, and progressive left facial palsy of recent onset. The biopsy specimen taken from either side after surgical debridement revealed only nonspecific inflammatory granulation tissue, but the culture of the tissue was positive for Aspergillus flavus. Invasive aspergillosis was confirmed by demonstration of the fungi in the tissues with Gomori-Methanamine Silver staining. The patient was hence put on long-term Itraconazole therapy and is presently doing well. The possibility of invasive fungal otitis always needs to be considered as a differential diagnosis in immuno-compromised patients presenting with atypical otomastoiditis so as to diagnose this rare condition at an early stage to reduce the delay in the treatment and prevent its possible complications such as skull base osteomyelitis and progressive cranial nerve palsies.
Keywords: Bilateral presentation, Fungal otitis, Invasive aspergillosis, Itraconazole
|How to cite this article:|
Bradoo RA, Shah KD, Gayathri H, Kapadia MA. Invasive aspergillosis of the temporal bone. Indian J Otol 2012;18:30-3
| Introduction|| |
Aspergillus are ubiquitous saprophytic moulds, commonly found on decaying material around the world. Inhalation of the spores (Conidia) causes fungal sinus infections and diffuse lung infections, which subsequently spread to other sites. Invasive aspergillosis of temporal bone is an extremely rare entity, although aspergillus species are the most common fungi implicated in superficial otomycosis. The first case was described in 1985 in a 68-year-old man with relapsing acute myeloid leukemia.  Since then, very few isolated cases have been reported in literature. We report a case of bilateral invasive aspergillosis of temporal bone in an elderly diabetic patient.
| Case Report|| |
A 65-year-old man presented with bilateral ear discharge and hearing loss since 1 year. He had developed progressive left-sided facial weakness since 15 days. He was a known diabetic since 5 years, on irregular treatment. On local examination of the ear, lobulated pinkish-red subepithelial mass was seen in the external auditory canal (EAC) on both sides, and normal tympanic membrane (TM) could not be appreciated [Figure 1]. Left-sided facial weakness was present (House-Brackmann Grade V). Other cranial nerve examination was normal. Rest of the ear, nose and throat (ENT) examination was unremarkable. On admission, initial laboratory workup revealed raised erythrocyte sedimentation rate ESR (90 mm/h) and abnormal blood sugars (fasting blood sugar - 598 mg/ dL, post-prandial blood sugar - 672 mg/dL). The urine was negative for ketone bodies. Left ear discharge sent for gram stain, and antibiotic culture sensitivity revealed no bacterial growth. The patient was started on broad-spectrum antibiotics in view of probable bilateral unsafe chronic otitis media or necrotizing otitis externa along with appropriate dose of insulin for strict diabetic control.
|Figure 1: Bilateral subepithelial masses (pointed by arrows) filling external auditory canal, seen on otoendoscopy. R - right, L - left|
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High-resolution computed tomography scan of temporal bone was planned in order to note the extent of the pathology and delineate the affected site of the facial nerve. The scan demonstrated soft tissue lesion filling the EAC on the left side, eroding the posterior canal wall and vertical part of facial canal from 2 nd genu to stylomastoid foramen. Similar soft tissue lesion was seen partly filling right EAC and middle ear, extending into the Eustachian tube More Details. The TM was thickened on both sides. Bilateral partial opacification of mastoid air cells was noticed, although the intervening septae were preserved [Figure 2].
|Figure 2: Axial high-resolution computed tomography scan of temporal bone demonstrating R (right) - soft tissue lesion (*) involving the tympanic membrane (TM) and external auditory canal (EAC) L (left) - soft tissue lesion (a) involving the TM and EAC with erosion of posterior canal wall and facial canal near 2nd genu (b)|
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Left ear exploration with facial nerve decompression was planned. Intraoperatively, mass was seen to be arising from posterior canal wall, eroding adjacent bone, abutting vertical part of the facial nerve in its entire extent. The mass could be dissected off the nerve. The tympanic membrane was thickened by the disease process, although there was no evidence of epithelial breach. Glue was present in the middle ear. Ossicles were found to be intact. There was no evidence of any cholesteatoma sac. Postoperatively, no improvement of the facial nerve function was noticed.
Histopathological examination of the left ear mass revealed only nonspecific inflammatory granulation tissue rich in lymphocytes, plasma cells, eosinophils, and neutrophils with no evidence of any granuloma covered with acanthotic epithelium.
In view of the bilateral nature of disease, long-standing pathology, and masses being purely subepithelial, ANA, ANCA, and ACE were done to rule out any connective tissue disorder, Wegener's granulomatosis, or Sarcoidosis, but the immunological workup also turned out to be negative.
In the absence of any diagnosis and in view of similar appearance of the right-sided lesion, right ear exploration was done to obtain more tissue for diagnosis. Intraoperatively, the subepithelial mass in the right ear was found to be arising from the thickness of the tympanic membrane, partly involving the anterior and posterior canal wall. Erosion of the floor of EAC was seen. Disease was extending into the middle ear and Eustachian tube and was surrounding the ossicles. Incudo-stapedial joint was necrosed and disease found to be covering the stapes. In order to prevent any inadvertent damage to inner ear, disease was left behind in stapes area.
The right-sided mass on histopathological examination also revealed nonspecific inflammatory granulation tissue. Staining and culture for tubercular bacilli were negative. Culture of the tissue on Sabouraud's dextrose agar demonstrated yellowish green granular mould with radial conidia suggestive of Aspergillus flavus. Gomori-Methanamine Silver (GMS) staining on the biopsy tissue demonstrated the acutely branching hyphae confirming the presence of aspergillus in the tissue [Figure 3].
|Figure 3: Photomicrograph of the right ear mass showing acutely branching hyphae with conidiospores embedded within the tissue on Gomori- Methanamine Silver staining on low (10x) - (a) and high (48x) magnification - (b)|
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The patient was started on Tab. Itraconazole 200 mg BD. Presently after 2 months of antifungal therapy, the ear lesions have shown resolution as per clinical examination. The left facial paresis has improved from grade V to grade III. The patient continues to be under regular follow-up.
| Discussion|| |
Fungal infection of EAC, otomycosis, is a very common condition without morbidity. But manifest fungal infection of middle ear, invasive aspergillosis, is extremely rare and is mostly seen in immuno-compromised patients, such as those with leukemia, AIDS, diabetes mellitus, and patients on immunosuppressive therapy. Very few cases have been reported in immuno-competent individuals. 
Hall and Farrior had classified aspergillosis of temporal bone into three forms: a non-invasive form; an invasive form, which causes bone invasion, has a granulomatous response, and is seen in immuno-competent individuals; and a fulminant form that occurs in immuno-compromised patients and is characterized by tissue and angioinvasion, rapid progression, and minimal tissue reaction. 
Patients with invasive aspergillosis of temporal bone can have similar presentation as necrotizing otitis externa caused frequently by Pseudomonas sp., although the fungal infection has a more protracted course, is more invasive, with higher chances of facial palsy when compared to its bacterial counterpart. 
Demonstration of fungi on culture alone isn't conclusive of invasive fungal otitis, as colonization with saprophytic fungi in chronic otitis media and superficial fungal otitis externa is more common.  Demonstration of the fungus in the tissues, as was done in our case with GMS staining, is essential to confirm the invasive nature of the fungal infection.
The histopathological examination of the lesion in our patient revealed only nonspecific inflammatory granulation tissue without any granulomatous response. The disease in our patient had a chronic course although he did not have any granuloma formation and hadn't progressed as rapidly as the fulminant form.
Once the diagnosis is confirmed, treatment of aspergillus otomastoiditis consists of antifungal therapy and attempts to control underlying immunodeficiency along with surgical debridement. Hyperbaric oxygen therapy can be considered in refractory cases, although the evidence for its efficiency is still lacking. 
Antifungal agent of choice was traditionally Amphotericin-B,  which has fallen out of favor in view of its severe systemic side effects. Itraconazole has been tried with successful outcome, either alone or with Amphotericin-B in a few cases.  Voriconazole, the newer azole, has been found to be more effective against aspergillus sp. when compared to other azoles and Amphotericin-B,  although the cost of the drug is a serious concern and was the restraining factor in using this drug in our patient as well. There has been no uniform consensus on duration of the antifungal therapy, with different case reports mentioning variable duration ranging from 3 weeks to 77 weeks. 
Aggressive surgical debridement has been done in most of the cases reported except for two cases, which had fared well even with minimal or no surgical debridement.  In our case, extensive debridement was done on the left side but wasn't feasible on the right side due the disease engulfing the stapes.
| Conclusion|| |
Invasive aspergillosis of temporal bone is an extremely rare entity and still remains a diagnostic challenge. It needs a high degree of suspicion to arrive at a diagnosis, so as to initiate therapy early in this potentially lethal disease.
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[Figure 1], [Figure 2], [Figure 3]