Diffuse bone-marrow metastasis of grade 4 isocitrate dehydrogenase-mutant astrocytoma associated with hematological abnormalities: Gliomatosis of the bone marrow.

Background: Diffuse bone-marrow metastasis of high-grade glioma associated with hematological abnormalities is extremely rare.

Case description: A 32-year-old man was referred and admitted to our hospital for treatment of three remote recurrent brain lesions. He had been treated at the referring hospital for a primary brain tumor in the right frontal lobe. One of the recurrent lesions was resected and diagnosed as a grade 4 isocitrate dehydrogenase (IDH)-mutant astrocytoma. Stereotactic radiation therapy (SRT) was performed on all three lesions. During this hospitalization, a lumbar spine magnetic resonance imaging (MRI) showed signal changes in the first and fourth vertebral bodies, suggesting lumbar metastasis. In addition, blood tests showed a gradual increase in the lactate dehydrogenase (LDH) level. Three months later, the patient was referred to our hospital again for palliative SRT of metastatic lumbar vertebral lesions invading the psoas major muscles. Laboratory data showed pancytopenia and a marked increase in the LDH level. A lumbar spine MRI showed signal changes in all lumbar and sacral vertebrae. To rule out hematological malignancy, biopsies of the psoas major and iliac bone marrow were performed. They showed invasion of grade 4 astrocytoma cells in both areas, leading to a diagnosis of diffuse bone-marrow metastasis. The patient died 12 days after the second admission.

Conclusion: We present a rare case of diffuse bone-marrow metastasis of grade 4 IDH-mutant astrocytoma associated with hematological abnormalities. Progressive LDH elevation might predict diffuse bone-marrow metastasis in patients with high-grade glioma.