Implantation metastasis along the stereotactic biopsy tract in anaplastic astrocytoma: a case report.

Abstract

Stereotactic biopsy for brain lesion is usually a safe procedure and the reported rate of complication is minimal. Moreover, local seeding along the trajectory of the stereotactic biopsy is arare complication. The authors report a case of metastatic implantation along the trajectory of the stereotactic biopsy in anaplastic astrocytoma. A 64-year-old man who presented with a one-month history of speech and memory disturbance underwent magnetic resonance (MR) imaging that disclosed a large mass in the left basal ganglia and medial temporal region. Under the impression of high-grade glioma, computed tomography guided stereotactic biopsy was performed using the Riechert-Mundinger system. The histologic diagnosis was anaplastic astrocytoma. MR images after two cycles of chemotherapy showed a small enhancing portion in the middle of the biopsy tract, which was considered a surgical artifact and not included in the field of the following conventional fractionated radiation therapy. MR images three months after the completion of radiation therapy revealed that the enhancing portion had become a larger mass irrespective of good control of the primary tumor. Our findings suggest that tumor seeding along the stereotactic biopsy trajectory must be considered if an enhancing lesion appears in the MR image following the stereotactic biopsy. The cause and the prevention of implantation metastasis along the stereotactic biopsy tract are also discussed.