Meningioma of the internal auditory vanal: case report

Abstract

-Meningiomas limited to the internal auditory canal (IAC) are rare. Acoustic neuroma is usually the diagnosis made when a tumor is found in this location because of its higher frequency. We report on a 58 year-old woman with a meningioma arising from the IAC and the difficulty to establish the pre-surgical diagnosis, based on clinical and radiological features. The perioperative suspicion and confirmation are very important to deal with the dura and bone infiltration in order to reduce tumor recurrence.KEY WORDS: meningioma, internal auditory canal, acoustic neuroma. Meningioma do meato acústico interno: relato de casoRESUMO -Meningiomas restritos ao meato acústico interno são raros. O neurinoma do acústico é o principal diagnóstico diferencial feito quando um tumor é encontrado nesta região devido a sua maior freqüência. Apresentamos o caso de uma mulher de 58 anos de idade com meningioma localizado no meato acústico interno e as dificuldades na realização do diagnóstico pré-operatório considerando-se as apresentações clínica e radiológica. A suspeita e a confirmação do diagnóstico intraoperatório são importantes porque a dura subjacente e eventual osso comprometido devem ser ressecados para reduzir a possibilidade de recidiva.PALAVRAS-CHAVE: meningioma, meato acústico interno, neurinoma do acústico. Meningiomas are the second most common tumor of the cerebellopontine angle (CPA) accounting for 3.1 to 12 % of all tumors following acoustic neuroma, which represent 76 to 91.3 % of the total [1][2][3] . Usually CPA meningiomas arise from the dura of the petrous bone and are classified according to their origin, in relation to the International Auditory Canal (IAC) 4 . Meningiomas arising within the IAC are considered rare; only 22 cases of these tumors were reported in the literature [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] , eleven cases were limited to the IAC, while the others also extended to the CPA. Controversy exists in the literature if the meningioma can arise within the IAC or its involvement occurs secondarily by extension of CPA tumors 5 . The first histologically proven case of a purely intracanalicular meningioma was reported by Virchow in 1863 6 . In the present report we describe a meningioma of the IAC and the difficulty to establish the preoperative diagnosis, since the clinical findings can simulate an acoustic neuroma and the radiological examination can also be quite similar [4][5][6][7][8][9][10][11][12][13]18 . The surgical strategy is also discussed. CASEA 58 year-old female presented in May 2002 with a 2-month history of sudden hearing loss and tinnitus on the right. A retro-cochlear disease diagnosis was made based on auditory examinations. The pure-tone audiometry revealed a left descendent sensorineural hearing loss, mild at 500 and 1000 Hz and severe at 8000 Hz. The right speech discrimination score was 72% with monosyllables and 92% with disyllables, the left year score was 100% with monosyllables. The imitanciometry revealed a bilateral A curve at the tympanogr...

Meningioma of the Internal Auditory Canal With Rapidly Progressive Hearing Loss -Case Report-

“…2) Early hearing loss over a few years is a characteristic of IAC meningiomas, but rapidly progressive hearing loss was reported in only two cases, over a period of 2 months. 1,9) Rapidly progressive hearing loss in cases of VS was reported previously. 6,12) Rapidly progressive hearing loss in patients with Neurol Med Chir (Tokyo) 51, March, 2011…”

“…13) The most common symptoms of IAC meningiomas are tinnitus and hearing loss, whereas rapidly progressive hearing loss is very unusual. 1,9) We report an unusual case of IAC meningioma with rapidly progressive hearing loss over one month.…”

Meningiomas of the Internal Auditory Canal

“…Interestingly, all patients with preoperative facial palsy were meningothelial or angiomatous meningiomas, as were all cases with infiltrated facial and cochlear nerves. The prevalence of the different histopathologies in literature (when described) resulted in meningothelial meningioma in 76% of the cases and psammomatous in 19% 6,8,12,16,21,24,27,30,32,35 . Rare cases of transitional meningioma have also been published 16,24…”

“…In literature, hearing preserving techniques were used in more than 50% of the patients, despite many patients having suffered from preoperative anacusis or unserviceable HL. Among the remaining patients with preoperative class A to C hearing, fewer than 63% maintained hearing 8,16,18,20,22–24,27,28,30,33,34 . It is thus imperative to decide the appropriate approach, considering the importance of an adequate tumor removal over the confined possibilities of hearing preservation with surgery.…”

“…There have been less than 50 cases of pure ICMs described in literature and nearly 100 IAC meningiomas extending partly in the CPA (largest series are collected in Table I). 6–8,11–36 …”