To report the first Chinese case of complex mosaic neurofibromatosis type 2 (NF2)—recently reclassified as NF2-related schwannomatosis—in a patient presenting with concurrent severe visual impairment and an intracochlear schwannoma, and to evaluate the clinical efficacy and strategic priority of tumor-preserving in situ cochlear implantation (CI).

The patient’s clinical presentation, extensive neurosurgical history, genetic profile, and perioperative audiological data were retrospectively reviewed. Additionally, we analyzed the surgical approach—which involved localized microdrilling of the obstructed cochlear turn—and the subsequent one-year follow-up outcomes of auditory-verbal rehabilitation.

A 52-year-old female presented with bilateral vestibular schwannomas and secondary profound sensorineural hearing loss. Peripheral blood genetic testing revealed no pathogenic NF2 mutations, strongly indicating somatic mosaicism. The patient also suffered from a concurrent profound visual deficit due to bilateral optic atrophy and exhibited a right-sided intracochlear schwannoma. Successful tumor-preserving in situ cochlear implantation (CI) was performed on her right ear by bypassing the tumor obstruction along the cochlear trajectory. At the one-year postoperative follow-up, the patient achieved significant gains in aided hearing thresholds, along with a disyllabic word recognition score of 22%. Furthermore, her Category of Auditory Performance (CAP) score markedly improved from 0 to 6, and her Speech Intelligibility Rating (SIR) score reached level 5.

Cochlear implantation (CI) with tumor preservation in situ represents a safe, viable, and highly effective hearing reconstruction strategy for complex NF2 patients with intracochlear schwannomas. For patients afflicted with dual sensory impairment (dual sensory loss), a successful cochlear implant serves as a critical standalone interface that significantly facilitates auditory-verbal rehabilitation and restores social autonomy, even within an intricate oncological landscape.