[Extraneural metastasis of brain and spinal cord tumors. Report of 2 cases].

This case report refers to two patients with the rare entity of an extraneural metastasizing central nervous system tumor. The first patient presented with ipsilateral cervical lymph node metastases 4 years after a diagnostic biopsy and 2 years after removal of an anaplastic oligodendroglioma, respectively. The origin of the metastases was confirmed by immunohistochemistry. The second case described was found in a 26-year-old female who had suffered from a spinal cord pilocytic astrocytoma in infancy and been treated by surgery and radiotherapy. On postmortem examination, transformation to a primitive neuroectodermal tumor was found. Morphological and immunohistochemical features of the metastases were exactly identical with those of the primary tumors in both cases. The pathomechanisms of metastasizing CNS tumors are discussed with reference to the reasons why such cases are so rarely observed. The incidence of remote metastases and differences depending on tumor type are estimated. No relation to malignancy grade can be detected.