[Rare tumor of internal auditory canal]

Objective: To explore the clinical features and treatment strategy of rare tumor in the internal auditory canal(IAC). Methods: A retrospective study was carried out in 213 patients with lesion of ICA form January 2010 to December 2020. According to imaging features, surgical findings, and pathological diagnosis, there were 7 cases of non-sporadic acoustic neuroma, including 2 cases of cavernous hemangioma, 2 cases of aneurysm, 1 case of intralabyrinthical schwannoma, 1 case of meningioma, and 1 case of unilateral neurofibromatosis type 2 (NF2). The clinical manifestations, imaging data and intraoperative conditions as well as the formulation of individualized treatment strategies and prognosis were comprehensively analyzed. Results: In addition to hearing loss, cavernous hemangioma early appeared damage of facial nerve. CT showed expansion and calcification of IAC. Patients with aneurysm appeared tinnitus and vertigo early. CT showed enlargement of ampulla shape of IAC. DSA or MRA can help confirm the diagnosis. Patients with intralabyrinthine schwannoma early appeared refractory vertigo. High resolution MRI was helpful for diagnosis. "Dural tail sign" can be seen on enhanced MRI of meningeoma. Neurofibromatosis type 2 usually presented as bilateral vestibular schwannomas,but a few patients presented only with unilateral vestibular schwannomas.. All patients underwent labyrinth approach resection except one patient with NF2 for followed-up. Their postoperative symptoms were relieved. No tumor recurrence was observed during 6-3 years of follow-up. Conclusions: The clinical and imaging manifestations of rare tumors of the internal auditory canal are different. The principle of treatment is also different. It is helpful to avoid the serious consequences caused by blind operation to confirm diagnosis before operation.