Vestibular Dysfunction as a Novel Presentation of Middle Ear Neuroendocrine Tumor.

Objectives: This study aimed to contribute to the sparse literature on middle ear neuroendocrine tumors (MeNETs) by detailing a unique case of MeNET-associated cochlear-vestibular dysfunction and outlining diagnostic, therapeutic, and follow-up considerations.

Design: A single-patient case report.

Setting: A tertiary academic referral center.

Participant: A 40-year-old male presenting with profound left sensorineural hearing loss (SNHL), left vestibular hypofunction, and a middle ear mass.

Main outcome measures: Histopathologic confirmation of MeNET, radiological identification of residual disease, postoperative symptom progression, and rehabilitation outcome.

Results: Clinical evaluation, imaging, and histopathology confirmed the diagnosis of MeNET. Immunohistochemistry revealed positivity for chromogranin, synaptophysin, insulinoma-associated protein 1 (INSM1), cytokeratin mouse monoclonal antibody (CAM 5.2). An endoscopic middle ear exploration with tympanoplasty and canalplasty was performed, followed by vestibular rehabilitation. Surveillance with DOTA-Tyr3-octreotate PET/MRI identified residual disease, leading to a revision mastoidectomy. The patient experienced persistent imbalance postoperatively, requiring vestibular rehabilitation, and profound SNHL, for which a hearing aid evaluation was recommended.

Conclusions: This case represents the first report of MeNET-associated cochlear-vestibular dysfunction. The significance of this report lies in the unique clinical presentation, the role of advanced imaging for surveillance, and the need for revision mastoidectomy following an initial endoscopic approach. This report discusses the challenges in achieving complete tumor clearance and emphasizes the need for continued case documentation and research into adjunctive therapies.