Concomitant Occurrence of Vestibular Schwannoma and Epidermoid Cyst in Neurofibromatosis: Case description and Review of the Literature

We report a case of a 16-year-old female patient harboring neurofibromatosis type 2 who presented with bilateral hearing impairment, which was on the left side, as well as facial paresis (House-Brackmann grade III) and ataxic gait. A magnetic resonance imaging (MRI) exam evidenced bilateral lesions in the cerebellopontine angles (CPAs) with extension into the internal acoustic meatus, and an additional lesion in the right CPA with radiological characteristics of an epidermoid cyst. The patient was submitted to microsurgical resection, confirming a collision of a vestibular schwannoma and an epidermoid cyst in the right CPA. In the present case report, we describe the first case reported in the literature with preoperative diagnostic work-up, intraoperative findings, postoperative course of the patient, as well as a detailed literature review of these specific coinciding pathologies, denoting the importance of further genomic studies regarding multiple central nervous system (CNS) lesions.

Relatamos o caso de uma paciente de 16 anos de idade com neurofibromatose tipo II com deficiência auditiva bilateral, pior no ouvido esquerdo, assim como paresia facial (HouseBrackmann grau III) e ataxia. Estudo de ressonância magnética comprovou lesão bilateral nos ângulos cerebelopontinos (ACPs) com extensão ao meato acústico interno, e uma lesão adicional no ACP direito com características radiológicas de um cisto epidermoide. A paciente foi submetida a ressecção microcirúrgica, confirmando a colisão de um schwannoma vestibular com um cisto epidermoide no ACP direito. No presente estudo, descrevemos o primeiro caso relatado na literatura com trabalho diagnóstico pré-operatório, resultados intraoperatórios, evolução da paciente no pós-operatório, assim como revisão detalhada da literatura específica sobre essas patologias, demonstrando a importância de mais estudos genômicos sobre as múltiplas lesões do sistema nervoso central (SNC).

[Intraoperative monitoring of cochlear nerve function during cerebello-pontine angle surgery]. / Intraoperatives Monitoring des N. cochlearis bei Eingriffen im Kleinhirnbrückenwinkel.

BACKGROUND: Surgical procedures in the cerebello-pontine angle (CPA), e. g. for vestibular schwannoma, have an increased risk for damage to the cochlear nerve. Consequently, hearing deterioration up to complete deafness may result with severe impact on quality of life. Methods for intraoperative monitoring of function may minimize such risks. OBJECTIVE: Review of current methods for intraoperative monitoring of the cochelar nerve and summary of new developments. MATERIALS AND METHODS: Analysis and summary of literature, discussion of new methods. RESULTS: Early auditory evoked potentials using click stimuli remain the standard method for intraoperative monitoring of cochlear nerve function. Amplitude and latency changes indicate a risk of postoperative hearing deterioration; however demonstrate only limited further differentiation of hearing quality. As novel methods, near-field recordings may allow faster feedback and auditory steady state responses potentially enable frequency specific testing. CONCLUSIONS: Intraoperative monitoring of the cochlear nerve is an integral component of CPA surgery. It enables detection of potential nerve damage and thus contributes to avoiding postoperative functional deficits. Development and implementation of novel and additional approaches may further improve its clinical value.

Quiste aracnoideo bilateral del ángulo pontocerebeloso / Bilateral cerebellopontine arachnoid cyst

Introducción. Los quistes aracnoideos bilaterales del ángulo pontocerebeloso son excepcionales, y únicamente existen tres casos publicados en la bibliografía. Caso clínico. Niña de 14 años, previamente sana, que acude a consultas por presentar cefalea bifrontal de seis semanas de evolución. La exploración clínica era normal y la resonancia magnética craneal mostraba dos lesiones extraaxiales localizadas en ambos ángulos pontocerebelosos, siendo ligeramente mayor la izquierda. Las lesiones se comportaban como homogéneamente intensas en T1 e hiperintensas en T2, no captaban contraste y no existía restricción en las secuencias de difusión. No se indicó tratamiento quirúrgico. Conclusiones. Los quistes aracnoideos bilaterales situados en el ángulo pontocerebeloso son excepcionales. La principal indicación para el tratamiento quirúrgico es la presencia de síntomas o signos neurológicos coincidentes con la localización de los quistes (AU)

Introduction. Bilateral cerebellopontine arachnoid cysts are very rare, and only three cases have been previously reported. Case report. A 14-year-old previously healthy girl presented to our outpatient clinic with a 6-weeks history of frontal headache. They typically would start in the occipital region and then radiate bifrontally. The neurological examination was unremarkable. Magnetic resonance imaging revealed an extra-axial bilateral lesion in bilateral cerebellopontine angle, larger on left side. The lesions were homogeneously hypointenese on T1 -weighted imaging and hyperintense on T2- weighted imaging without evidence of contrast enhancement and without evidence of restriction on diffusion-weighted imaging. No surgical treatment was indicated. Conclusions. Bilateral arachnoid cysts of the cerebellopontine angle are very infrequent and the main indication for surgery is the existence of clinical symptoms or neurological deficit coincident with the locations of the cysts (AU)

Melanocitoma meníngeo del ángulo pontocerebeloso, ¿Un tumor benigno? / Cerebellopontine angle meningeal melanocytoma: a benign tumor?

Se presenta un paciente con un raro melanocitoma meníngeo del ángulo pontocerebeloso que, tras su extirpación quirúrgica radical, evolucionó en el plazo de un año hacia una melanomatosis meníngea fulminante. Se realiza una revisión bibliográfica en busca de las claves para hacer una aproximación diagnóstica preoperatoria de este tipo de tumor y obtener información sobre su tratamiento y manejo postoperatorio (AU)

We report a case of a rare meningeal melanocytoma in the cerebellopontine angle. One year after tumor gross total removal, the patient suffered a sudden and devastating meningeal melanomatosis. The relevant literature is reviewed looking for the keys to establish preoperative diagnosis and to obtain information about its treatment and postsurgical management (AU)

The effect of intracranial surgical trauma on gadolinium-enhanced magnetic resonance imaging.

Gadolinium-enhanced magnetic resonance imaging (MRI) is currently the gold standard for diagnosis of an acoustic neuroma. Its status is diagnosis of a recurrent or residual neuroma is not nearly as clear. A pilot study of 36 postoperative cases showed enhancement in 100% of the patients at the operative site. To examine the role of surgical trauma and biodegradable packing on enhanced MRI, an animal study was designed. Cats and monkeys that underwent posterior fossa surgical procedures had preoperative and postoperative MRI and histologic correlation of any enhanced area. Areas of postoperative enhancement should not be considered as diagnostic of tumor. Further studies are necessary to develop a criteria for recurrent tumor diagnosis with enhanced MRI.