K Aubry1, M Wassef, J-P Guichard, P Herman, P Tran Ba Huy. 1. Service d'ORL, hôpital Lariboisière, AP-HP, faculté de médecine, université de Paris Diderot-Paris 7, 2, rue Ambroise-Paré, 75010 Paris, France.
Abstract
OBJECTIVES: We report a case of an association of an arachnoid cyst with heterotopic neuroglial tissue in the internal auditory canal. MATERIAL AND METHODS: A 66-year-old woman consulted for cochleovestibular syndrome. RESULTS: MRI demonstrated a lesion with spontaneous hypersignal on T1- and T2-weighted images, instigating surgical exploration. We discovered a hematic arachnoid cyst associated with heterotopic neuroglial tissue arising in the internal auditory canal. CONCLUSION: An arachnoid cyst arising within the cerebellopontine angle or the internal auditory canal is a rare occurrence. Clinical manifestations are identical with those produced by a cochleovestibular schwannoma. MRI usually demonstrates a nonenhancing isointense cystic mass with cerebrospinal fluid on all sequences (hypointense on T1-weighted and hyperintense on T2-weighted images). These lesions are usually monitored. Spontaneous hypersignal on T1- and T2-weighted images makes diagnosis difficult, as in our case, leading to surgical exploration.
OBJECTIVES: We report a case of an association of an arachnoid cyst with heterotopic neuroglial tissue in the internal auditory canal. MATERIAL AND METHODS: A 66-year-old woman consulted for cochleovestibular syndrome. RESULTS: MRI demonstrated a lesion with spontaneous hypersignal on T1- and T2-weighted images, instigating surgical exploration. We discovered a hematic arachnoid cyst associated with heterotopic neuroglial tissue arising in the internal auditory canal. CONCLUSION: An arachnoid cyst arising within the cerebellopontine angle or the internal auditory canal is a rare occurrence. Clinical manifestations are identical with those produced by a cochleovestibular schwannoma. MRI usually demonstrates a nonenhancing isointense cystic mass with cerebrospinal fluid on all sequences (hypointense on T1-weighted and hyperintense on T2-weighted images). These lesions are usually monitored. Spontaneous hypersignal on T1- and T2-weighted images makes diagnosis difficult, as in our case, leading to surgical exploration.