Pilocytic Astrocytoma of the Cerebellopontine Angle in a Child Presenting with Auditory Neuropathy Spectrum Disorder
Otology & Neurotology 00:00Y00 Ó 2014, Otology & Neurotology, Inc. Imaging Case of the Month Pilocytic Astrocytoma of the Cerebellopontine Angle in a Child Presenting With Auditory Neuropathy Spectrum Disorder *Frederike Schneider, *Martin Kompis, †Christoph Ozdoba, ‡Ju¨rgen Beck, *Marco Caversaccio, and *Pascal Senn *University Department of Otorhinolaryngology, Head and Neck Surgery, ÞUniversity Institute of Diagnostic and Interventional Neuroradiology, and þUniversity Department of Neurosurgery, Inselspital, Bern, Switzerland Auditory neuropathy spectrum disorder (ANSD) is a preserved transient evoked OAEs (TEOAEs), and patho- clinical syndrome with hearing loss characterized by logic BERA findings on the left side indicating unilateral measurable otoacoustic emissions (OAEs) and absent or ANSD (Fig. 1). On the right side, all tests were normal abnormal brain stem evoked response audiometry find- (Fig. 1). ings (BERA) (1,2). Routine magnetic resonance imaging The unenhanced, T2-weighted axial images showed a (MRI) has been advocated in children with ANSD be- large, partially cystic, expansive tumor in the cerebello- cause cochlear, neural, or central abnormalities are ob- pontine angle (CPA) on the left side with displacement of served in up to 64% of affected cases (2). In the two the brain stem and the lower Cranial Nerves VII and VIII largest reported imaging series comprising a combined (Fig. 1). Postgadolinium axial and coronal sequences total of 221 children, developmental malformations, such showed strong enhancement of the CPA lesion (Fig. 2). as cochlear nerve deficiency or hindbrain malformations, A retromastoidal craniotomy with subtotal tumor re- were predominantly observed, suggesting a benign origin moval was performed in the neurosurgery department. of ASND in general. Bilateral ANSD cases are approxi- Total resection was not possible because of unclear bor- mately 4 times more frequently associated with intracra- ders between tumor mass and vital brain stem structures.
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