Low-Grade Primary Intramedullary Spinal Cord Astroblastoma: A Case Report and Literature Review.

Spinal astroblastoma is an exceedingly rare entity characterized by features that overlap with other spinal cord tumors. We present a case of a 67-year-old male who presented with trunk dysesthesia, motor weakness, and progressive hypoesthesia in both lower limbs. Magnetic resonance imaging (MRI) revealed edematous changes in the spinal cord at the C6-Th1 level on T2-weighted sequences, with a centrally enhancing lesion at the C7 level on gadolinium-enhanced T1-weighted imaging. Consistent with previous reports, spinal astroblastomas frequently involve the cervical and thoracic regions. Pathological examination in our case revealed pseudopapillary cellular arrangements surrounding hyalinized microvasculature. Immunohistochemical analysis demonstrated retained INI1/SMARCB1 expression and mixed-origin features, with positive staining for EMA, GFAP, OLIG2, neurofilament, and synaptophysin. The tumor exhibited low-grade characteristics, with no mitotic activity, necrosis, or significant MIB-1 index (0.3%), and followed a gradual clinical course. Genetic profiling revealed no MN1 alteration or fusion genes. Based on these findings, a diagnosis of low-grade spinal astroblastoma, not elsewhere classified, was made. In conclusion, spinal astroblastoma should be considered in the differential diagnosis of primary intramedullary spinal cord tumors, particularly those located in the cervicothoracic region and exhibiting mixed-origin features. The sharing of cases among clinicians is crucial for enhancing awareness and understanding of this rare pathology.