Pediatric vestibular schwannoma without evidence of neurofibromatosis: consecutive 18 microsurgical experiences

Sporadic vestibular schwannoma (VS) is rare in children in contrast to adults, and detailed investigations of case series of these patients using a single fixed protocol are scarce. This study presents our surgical experience of pediatric VSs without clinical evidence of neurofibromatosis type 2 (NF2) at the initial diagnosis.

Among 1385 consecutive sporadic VS surgeries, 18 pediatric patients (1.3%; 11-18 years old) were retrospectively investigated.

The most common initial symptom was hearing disturbance (72.2%), and 6 patients (33.3%) experienced a delayed diagnosis (over 2 years after initial symptom onset). Preoperative image characteristics of these tumors included a solid tumor, hypervascularity, and significant extension into the internal acoustic meatus, when compared with adults. Preoperative embolization was successfully accomplished for 2 recent hypervascular tumors. The tumor resection rate was 95-100% under sufficient intraoperative neuromonitoring, and no additional surgery was required during the follow-up period (average: 57.9 months). No patients experienced permanent facial nerve palsy, and serviceable hearing function was preserved in 6 of 11 patients. Signs of NF2, such as bilateral VSs, were not identified in any patients during the follow-up.

Safe and sufficient tumor resection was achieved under detailed neuromonitoring in pediatric patients with sporadic VS, although this tends to be difficult owing to hypervascularity, a small cranium, and significant meatal extension. Preoperative embolization may help safe resection of hypervascular tumors. Subsequent development of NF2 has not been observed up to the most recent follow-up, but careful observation is essential for these younger patients.