The possibility of seeding vestibular schwannomas through surgery: Limited experience with two cases

BACKGROUND: We present two exceptional cases of possible tumor seeding in benign vestibular schwannoma (VS) patients occurring years after initial microsurgical resection. CASE DESCRIPTION: We retrospectively analyzed the surgical management, histology and documented the growth of new tumor occurrence in close vicinity of the original schwannomas by serial magnetic resonance imaging over a period of 10 years. None of the patients had stigmata of neurofibromatosis, making it a reasonable assumption that the second tumor was due to surgical seeding during the first surgery. Moreover, in the second case, a microsurgical re-exploration showed that the recurrent tumor did not show any adhesion or contact to the caudal cranial nerves as anticipated had this been a new cranial nerve schwannoma. CONCLUSIONS: Surgical seeding of VSs is a rare complication but can occur despite benign histology and generous irrigation during surgery.