[Intraosseous metastasis of K27-mutant glioma]. / Vnutrikostnoe metastazirovanie K27-mutantnoi gliomy.

Glioma metastasis outside the central nervous system is a quite rare phenomenon. The disease in a young woman manifested itself as back pain and loss of vision in the left eye. Magnetic resonance imaging (MRI) revealed a tumor of the optic nerve; positron emission tomography showed multiple secondary bone changes. At the same time, MRI detected no signs of neoplasm in the midline brain structures (the brain stem and subcortical nuclei) and spinal cord. Two biopsies (superior iliac spine trephine biopsy and optic nerve tumor biopsy) were performed. There were similar histological tumors; the optic nerve tumor was found to have K27M mutation in the H3F3A gene, whereas the metastatic tumor lacked this mutation (possibly due to the quality and quantity of DNA isolated from the tumor cells). The interesting features of this case are the simultaneous detection of primary and metastatic tumors before receiving any treatment and the absence of the K27M mutation in the H3F3A gene in the metastasis.

Extracranial growth of glioblastoma multiforme.

We present a 59-year-old woman who noted an enlarging lump on her forehead 6 months after a left frontotemporal craniotomy for tumor resection and chemoradiation of her primary glioblastoma multiforme (GBM). GBM is a highly aggressive intracranial neoplasm associated with the shortest survival time of any primary central nervous system malignancy. Extracranial metastasis is rare, especially without previous surgical disruption of the dura and calvarium, which has been postulated to cause seeding of the extracranial space with tumor cells. This patient's MRI revealed tumor recurrence for which she underwent repeat resection. Histopathology confirmed GBM with unmethylated O-6-methylguanine-DNA methyltransferase and wildtype isocitrate dehydrogenase 1 status, as well as tumor invasion through the bone and subdermal space. The genetic and molecular factors that predict extracranial invasion remain unclear and require further investigation. Emerging data on circulating tumor cells in GBM patients indicate that extraaxial metastasis may be part of the disease course in some, particularly in long term survivors. Furthermore, the proximity of calvarial and scalp lesions to previous surgical sites and the time course in which they emerge after surgery suggests that iatrogenic seeding may also play a role in metastasis. With heightened awareness of the phenomenon, surgical strategies such as watertight approximation of the dura, bone flap replacement, or changing surgical instruments once the intradural component is complete may prove useful to prevent seeding. Prophylactic craniospinal irradiation may also be an appropriate tool in patients at high risk for metastasis, although this population is difficult to identify.