Anaplastic oligodendroglial tumor metastatic to the bone marrow: Molecular heterogeneity of glial neoplasms and the clinical importance of minor clones

Abstract

Anaplastic oligodendrogliomas are primary brain tumors that rarely metastasize to extracranial sites. We present a case of a 37 year old man who presented at age 34 with a cystic, ring‐enhancing left parietal tumor. Partial resection revealed a synaptophysin‐positive anaplastic oligodendroglioma with a Ki‐67 labeling index of 17%; fluorescence in situ hybridization (FISH) revealed relative deletions of both chromosomes 1p and 19q. The patient subsequently received temozolomide (TMZ), radiotherapy (RT) plus TMZ, and post‐RT TMZ with continued progression of the tumor. Re‐resection 2 years later showed recurrent anaplastic oligodendroglioma with a Ki‐67 labeling index of 50% and he was started on procarbazine, lumustine, vincristine (PCV). Nine months later a third resection revealed anaplastic mixed oligo‐astrocytoma with a Ki‐67 index of 89% and loss of heterozygosity (LOH) 1p/19q. He was started on irinotecan and Avastin. Six months later he presented with night sweats and lower back pain. Bone marrow biopsy revealed a GFAP‐positive metastatic glioma histologically similar to the intracranial tumor; FISH studies revealed normal dosages of both 1p and 19q. These findings suggest that a minor clone in the primary brain tumor did not have LOH 1p and/or 19q and that this clone metastasized to the bone marrow.