Uncommon Lesions in the Internal Auditory Canal (IAC): Review of the Literature and Case Report

Rohlfs, Anna-Katharina and Burger, Ralf and Viebahn, Christoph and Held, Paul and Woenckhaus, Matthias and Roemer, Frank W. and Strutz, Juergen (2012) Uncommon Lesions in the Internal Auditory Canal (IAC): Review of the Literature and Case Report. JOURNAL OF NEUROLOGICAL SURGERY PART A-CENTRAL EUROPEAN NEUROSURGERY, 73 (3). pp. 160-166. ISSN 2193-6315

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Abstract

Background Despite the relatively frequent occurrence of multiple primary tumors, namely, 10% of intracranial tumors, metastasis is a rare occurrence within the internal auditory canal (IAC) and cerebellopontine angle (CPA). Intracanalicular metastases of adenocarcinoma are documented, but a primary adenocarcinoma remains unreported. We provide a review of uncommon lesions in the IAC and describe to our knowledge the first instance of a primary adenocarcinoma. Case Report A 60-year-old man presented with nausea and vomiting. Cranial computed tomography scan revealed bilateral nonspecific periventricular and subcortical vascular lesions. He presented 8 months later with left-sided tinnitus, progressive hearing loss, and attacks of vertigo. Magnetic resonance imaging (MRI) showed an extra-axial mass most likely representing a left-sided vestibular schwannoma with characteristic contrast enhancement in the IAC. The follow-up MRI showed an unchanged pattern of contrast enhancement. Due to progressive headaches and dizziness, the patient underwent a left transtemporal craniotomy with subtotal tumor resection. Histological examination revealed blennogenic cylindrical adenocarcinoma. The investigations for the primary tumor site were all negative. The patient's condition deteriorated gradually. MRI showed an increase of the residual tumor and meningeosis carcinomatosa, and cerebrospinal fluid (CSF) examination was positive for tumor cells. The patient was treated with intrathecal chemotherapy. He died of multiple organ failure. Discussion The discussion focuses on the incidence of extra-axial CPA and IAC lesions with their clinical presentations and their radiological findings. We address the issue of a possible regulation of CPA lesion laterality by asymmetrically expressed genes. In view of the sparse literature on treatment of single intracanalicular metastases, the review is broadened to the current treatment recommendations of single brain metastases. Conclusions The differentiation between benign and malign lesions in the CPA and IAC is important, as it requires diverse treatment protocols. For the physician this differentiation represents a clinical and radiological challenge. For the developmental research the left-right asymmetry might be a field of research.

Item Type: Article
Uncontrolled Keywords: SOLITARY BRAIN METASTASIS; FACIAL-NERVE FUNCTION; CEREBELLOPONTINE ANGLE; RANDOMIZED-TRIAL; VESTIBULAR SCHWANNOMA; LEPTOMENINGEAL CARCINOMATOSIS; STEREOTACTIC RADIOSURGERY; NEOPLASTIC MENINGITIS; HEARING PRESERVATION; CEREBRAL METASTASES; internal auditory canal; cerebellopontine angle; uncommon lesions; adenocarcinoma; left-right asymmetry
Subjects: 600 Technology > 610 Medical sciences Medicine
Divisions: Medicine > Lehrstuhl für Hals-Nasen-Ohren-Heilkunde
Depositing User: Petra Gürster
Date Deposited: 12 May 2020 08:18
Last Modified: 12 May 2020 08:18
URI: https://pred.uni-regensburg.de/id/eprint/18857

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