gms | German Medical Science

Objective: Metastatic seeding or iatrogenic implantation of vestibular schwannoma is a very rare phenomenon. There is only one published case in the literature so far. The authors present two cases of patients with previously resected vestibular schwannoma and the occurrence of new tumors with similar pathology distant to the original location.

Methods: Retrospective analysis of the surgical management, histological dignity and repetitive MR imaging over a period of ten years in two patients with iatrogenic seeding of vestibular schwannoma out of a total number of 1200 surgically treated.

Results: In one case a seeded tumor was first-time detectable at the abducens nerve in the MRI follow-up three years after removal of the vestibular schwannoma. This tumor manifestation showed a slow growth and did not cause any neurological symptoms. Radiation therapy was applied seven years after diagnosis. The other patient harbored a secondary schwannoma at the tuberculum jugulare without any attachment to cranial nerves, dura mater or brain parenchyma. This tumor was diagnosed during MRI follow-up eight years after tumor resection. In the following two years, the tumor demonstrated a rapid growth. Hence the tumor was resected after re-craniotomy of the retrosigmoid approach.

Conclusions: Seeding of vestibular schwannomas is a rare complication but can occur despite benign histology and generous irrigation during surgery. The growth behaviour does not seem to play a key role. Care must be taken during resection in order to minimize risk of secondary tumor implantation in the cerebellopontine angle.