Bilateral malignant metastases to the internal auditory canal: radiosurgical management
Marcos Dellaretti, Eduardo K. Tagawa, Julio Leonardo Barbosa Pereira, Mariana Pedrini, Baltazar Leão Reis and Atos Alves de Sousa
Malignant melanomas constitute 1-8% of all malignant tumors and are the third most common tumor to metastasize to the central nervous system. However, metastases to the cerebellopontine angle (CPA) are rare, accounting for only 0.2 to 0.7% of the lesions identified in this location
Case Report: A 62-year-old white man with a history of melanoma of the back, who had had all lesions completely excised, was reportedly tumor-free for 6 years. The patient presented bilateral metastatic CPA melanoma. Left side tumor was treated with surgery with partial resection (lost hearing) and radisorugery. Right side lesion was treated with radiosurgery and hearing preserved for 8 months, tumor controlled for 12 months, until death due to leptomeningeal carcinomatosis after 13 months of radiosurgey.
The patient underwent intensity-modulated stereotactic radiosurgery using BrainLab Iplan 4.1 for both IAC lesions, the dose was 18Gy prescribed to the 80% isodose line delivered by 11 fields. The patient presented no post-radiosurgery neurological complications.
Conclusion: In patients with lesions in the CPA, a diagnosis of melanoma should be included, particularly in cases with rapid progression of symptoms. Therefore, radiosurgery is a viable treatment option since the hearing can be preserved and tumor control achieved.
Keywords: Malignant melanoma, stereotactic radiosurgery, metastases