Primary spinal cord astroblastoma: a case report and systematic review of the literature detailing management and understanding histopathological, epigenetic, and molecular analysis.

Abstract

Objective: Astroblastomas (ABs) are rare glial tumors categorized by MN1 gene alterations in the WHO 2021 CNS tumor guidelines. While previously reported primarily in cerebral hemispheres, there have been few reports regarding primary spinal ABs, and no established guidelines have been published on the management of these lesions. Here, the authors present an illustrative case with a systematic review exploring presenting characteristics, diagnosis, management, and outcomes of spinal AB.

Methods: The patient's electronic medical record was retrospectively reviewed. Additionally, a systematic literature review was performed by searching the PubMed, Cochrane Library, Embase, and Web of Science databases for articles published through June 20, 2024, and all English-language articles describing patients with primary spinal AB were analyzed. Conference abstracts and articles describing secondary spinal AB or cerebral AB were excluded. Eleven previous cases of primary spinal AB were identified. Articles were screened by multiple reviewers to limit bias. For each case, clinical presentation, surgical pathology, molecular testing, treatment strategies, clinical course, and outcome were tabulated and compared.

Results: A 6-year-old male presented with thoracic back pain and limp and was found to have a high-grade thoracic AB with EWSR1::BEND2 fusion, treated with resection and radiation therapy; he is clinically stable at 12 months of follow-up. A systematic review yielded 11 prior cases; patient ages ranged from 3 months to 36 years, with most cases being pediatric. Clinical presentations commonly featured back pain, motor weakness, and gait disturbances. All cases except one underwent resection. Common pathological findings included perivascular hyalinization, pseudorosettes, pseudopapillae, high cellularity, and positive staining for glial fibrillary acidic protein/epithelial membrane antigen/S100. Molecular testing showed direct MN1 alteration in 6 cases, while the remaining cases showed MN1 methylation, EWSR1::BEND2 fusion, and MAMLD1::BEND2 fusion. Eight patients underwent chemotherapy, and 7 underwent radiation therapy. Except for 2 reported deaths, most patients were alive at the last follow-up (range 1 month-15 years). Progression of spinal AB occurred in one-third (4/12) of cases.

Conclusions: With the present report of a patient whose tumor exhibited EWSR1::BEND2 fusion, there are now 12 total reports in the literature of primary spinal AB. These cases span various pathological and molecular testing results, treatment strategies, and clinical courses. Given the diversity of current molecular signatures of spinal AB, this summative assessment of the current literature offers insights to inform guidelines for classifying AB and developing evidence-based treatment strategies going forward.