P12 | Bilateral internal auditory canal and leptomeningeal metastasis of non-small cell lung carcinoma mimicking neurofibromatosis type 2

Premises: Metastatic carcinoma in the internal auditory canal (IAC) or cerebellopontine angle is extremely rare. The most common primary tumor is lung cancer, being also the primary site with the highest rate of bilateral occurrence of IAC metastasis. Meningeal metastasis occur more frequently in bilateral diseases versus unilateral ones. Clinical and radiological features of bilateral IAC lesions can mimic neurofibromatosis type 2 (NF2), since IAC metastases on MRI appear similar to vestibular schwannomas and bilateral vestibular schwannomas are pathognomonic of this genetic disease, according to Manchester criteria.Description of the Case report: A 64 year old man was admitted to our ward with rapid-onset leg paresthesia, cauda equina syndrome and bilateral hearing loss. The patient was misdiagnosed as having NF2 due to MRI findings of bilateral internal auditory canals nodules, reported as vestibular neurinomas, and numerous foci of pathological contrastographic impregnation on the whole spinal cord’s surface, interpreted as meningiomas. The rapid worsening of the symptoms lead to reconsideration of the diagnosis and it turned out the patient was affected by multimetastatic non-small cell lung carcinoma.Conclusions: Although metastatic tumors in the IAC are rare, clinicians should be aware of this possibility. Patients with rapid-onset hearing loss, tinnitus, vertigo or facial palsy with radiological diagnosis of bilateral schwannomas should be tested in order to rule out IAC metastasis and to achieve an early identification of a possible malignancy and its primary site.