Stereotactic brain biopsies for histopathological diagnosis are a common technique in case of intracranial lesions, particularly in those not amenable for resection. Tumor seeding alongside the surgical trajectory after fine-needle aspiration is a known problem in several visceral tumors. Whereas in these cases a complete resection of the biopsy trajectory may later be performed, this strategy is not feasible in stereotactic brain biopsy. We report a case of tumor seeding along the entire biopsy tract after stereotactic biopsy of a brainstem metastasis. A 68-year-old male patient with a concomitantly diagnosed kidney lesion presented with a singular lesion in the brainstem. After confirmation of metastasis by stereotactic biopsy, stereotactic radiosurgery (SRS) was applied. The primary tumor was treated by laparoscopic nephrectomy. Three months after SRS, the patient presented with a secondary clinical deterioration for only a few weeks. The MRI scan showed tumor seeding along the entire biopsy tract. Salvage treatment including hypofractionated stereotactical irradiation and seven cycles of bevacizumab was administered to obtain symptom control. Massive seeding of tumor after stereotactic biopsy accordingly rare, taking into account that stereotactic biopsy is a very common neurosurgical intervention. Nonetheless, we think that the potential risk has to be kept in mind, as it might be neglected.
Keywords: Brainstem biopsy; Metastases; Radiosurgery; Stereotactic biopsy; Tumor seeding.