Gamma knife surgery is often used for treatment of brain metastases. A stereotactically-guided biopsy is performed to confirm the diagnosis in doubtful cases. Tumor cells that may spread as a result of the biopsy may survive and grow after gamma knife surgery, leaving a metastatic seeding through the biopsy tract. In this 45-year-old man, with a biopsy-proven metastatic adenocarcinoma, seeding was noticed after gamma knife surgery ([Figure]). This rare complication should be kept in mind when evaluating patients with brain metastases undergoing stereotactic biopsy followed by gamma knife surgery and not conventional radiation[1].
Figure Tumor seeding developing within the tract of a stereotactically-guided biopsy in a patient with metastatic adenocarcinoma from lung cancer further submitted to gamma knife surgery. Basal MRI shows a thalamic metastasis (left). Increasing tumor seeding along the surgical tract was noted four (center) and six months (right) after the procedure.
