Spinal astroblastoma: a rare tumour in an unusual location

Spinal Cord Astroblastoma With EWSR1-BEND2 Fusion in Female Patients: A Report of Four Cases From China and a Comprehensive Literature Review

Astroblastoma is an extremely rare central nervous system tumor characterized by astroblastic pseudorosettes and vascular hyalinization. Despite these histologic hallmarks, its morphology can vary, occasionally resembling other central nervous system tumors such as ependymoma. A novel tumor entity, astroblastoma, meningioma 1 (MN1)-altered, has been identified, featuring MN1 gene rearrangements typically involving BEN-domain containing 2 (BEND2) as a fusion partner. Most astroblastomas arise in the cerebral hemisphere. Here, we report 4 cases of spinal cord astroblastoma in female patients, all showing Ewing sarcoma RNA-binding protein 1 fusion with BEND2, rather than MN1. These tumors displayed growth patterns akin to traditional intracranial astroblastomas, with three cases demonstrating high-grade histology, including elevated mitotic activity and necrosis. Interestingly, some cases exhibited positive staining for pan-cytokeratin and hormone receptors. DNA methylation profiling clustered three of the four cases with the reference "AB_EWSR," whereas one case exhibited an independent methylation signature near the reference methylation group "AB_EWSR" and "pleomorphic xanthoastrocytoma." Together with the existing literature, we summarized a total of eleven cases, which predominantly affected children and young adults with female predilection. Eight of 10 patients experienced recurrence, underscoring the aggressive nature of this disease. We suggest recognizing a new molecular subgroup of spinal astroblastoma and recommend testing newly diagnosed infratentorial astroblastomas for Ewing sarcoma RNA-binding protein 1-BEND2 fusion.

Spinal astroblastoma, MN1 altered in 3-year-old child: An uncommon tumor at an unusual site

Astroblastoma is an uncommon circumscribed glial tumor mostly involving the cerebral hemisphere. The characteristic molecular alteration is meningioma (disrupted in balanced translocation) 1 (MN1) rearrangement. No definite World Health Organization grade has been assigned as both low- and high-grade tumors are known to occur. Tumors in the spine are extremely rare; to date only three cases have been reported in the literature. A vigilant microscopy and ancillary testing aid in diagnosis when the tumors present in unusual locations, as in our case. The prompt differentiation of this tumor from its mimickers is a mandate as modalities of management are different and not clearly established.

MN1 altered astroblastoma with APC and LRP1B gene mutations: a unique variant in the cervical spine of a pediatric patient

PURPOSE

Astroblastomas (AB) are high-grade neoplasms which typically occur within the cerebral hemisphere. However, given the rarity of this neoplasm and the number of variants, the relevance of this molecular makeup is unknown. We sought to describe the clinical presentation, treatment, and pathological analysis of a novel MN1 (meningioma 1) cervical spinal cord astroblastoma variant presenting in a pediatric patient.

METHODS

A retrospective review of electronic medical records was performed with an emphasis on neuroimaging, perioperative course, and pathological analysis.

RESULTS

An 11-month-old male with no significant history presented with two weeks of neck stiffness and cervicalgia. Neurologically, the patient was intact without signs of infection or trauma. Cervical CT was unremarkable. A subsequent MRI demonstrated a heterogeneously enhancing intramedullary lesion extending from the craniocervical junction to T4. The patient was treated with perioperative steroids and underwent C1-C3 laminectomies and C4-T4 laminotomies for tumor resection. Upon completion of the durotomy, an exophytic gray-red tumor was appreciated within the epidural space and gross total resection was achieved (no change on intraoperative neurophysiological monitoring) and confirmed on post-operative imaging. Immunohistochemical analysis was consistent with an astroblastoma with atypical diffuse positivity of CD56, CD99, and nuclear OLIG2. Molecular analysis revealed not only MN1 alterations but also changes in genes encoding APC and LRP1B. Both alterations were not previously documented to be associated with an astroblastoma.

CONCLUSION

Our case represents the first report of an infant with an MN1 astroblastoma with APC and LRP1B gene alterations in the cervical spine. Gross total resection paired with a detailed histopathologic analysis is vital for optimizing adjuvant treatment.