gms | German Medical Science

Objective: To report the surgical management of two collision tumors consisting of a vestibular schwannoma, a petroclival meningioma, a second vestibular schwannoma and a petrosal meningioma in a patient with NF 2.

Method: A 26-year-old woman presenting with a one-year history of hearing impairment in both ears (nearly deaf) and vision loss and impairment in the right and left eyes, respectively. During pregnancy she underwent magnetic resonance imaging, which revealed multiple intracranial lesions comprising two different lesions of each cerebellopontine angle (CPA) with contact to each other and brain stem compression. The patient underwent two surgeries. 1. Left CPA: In the first surgery, a left-sided retrosigmoid craniectomy was performed. The collision tumor (comprising a vestibular schwannoma and petroclival meningioma) of the left CPA was completely removed. Facial nerve reanimation using an end-to-end interposed sural nerve graft was indicated because of infiltration of the facial nerve by the vestibular schwannoma. The histopathological findings confirmed the diagnosis of collision between a schwannoma and a meningioma. After surgery, the patient had a complete facial palsy (H&B 6). 2. Right CPA: Aproximately nine months later, the patient underwent a right-sided retrosigmoid craniectomy. The petrosal meningioma and vestibular schwannoma were partially removed and an auditory brain stem implant (ABI) was placed on the cochlear nucleus of the pontomedullary brain stem through a single procedure. The facial nerve was preserved. Histopathological findings confirmed the diagnosis of a collision tumor between a schwannoma and meningioma. After surgery, the patient had no facial palsy (H&B 1).

Results: Follow-up examination in our outpatient ambulance showed that the facial nerve function on the left side recovered to HB grade III. The patient received useful auditory sensation after the auditory brain stem implant placement.

Conclusions: “Collision tumors” are rare, even in patients with NF-2 and have primarily been described in single-case reports. To our knowledge, to date, the collision of two collision tumors of both CPA has not been described. The surgical removal of these four tumors comprised a combined challenge pertaining to the removal of a vestibular schwannoma, petroclival meningioma, and petrosal meningioma in a patient with NF 2 and further strategies such as facial nerve reconstruction and placement of an ABI.