Clinicopathologic analysis of multifocal myxopapillary ependymoma: report of 4 cases and literature review

Abstract Objective Myxopapillary ependymoma (MPE) stands as a rare variant of ependymoma, primarily found within the spinal cord and cauda equina regions. This article aims to delve into the clinical and pathological characteristics of multifocal myxopapillary ependymoma (MPE), shedding light on its prognosis and advocating for increased awareness among clinical practitioners regarding this tumor type. Methods We conducted a retrospective analysis of clinical data, pathological morphology, immunohistochemical characteristics and next-generation sequencing (NGS) concerning four patients diagnosed with multifocal MPE. Additionally, relevant literature pertaining to this topic was thoroughly reviewed. Results The study encompassed two male and two female patients, aged between 20 and 57 years, with an average age of 34.6 years. Tumors were situated within the spinal canal, spanning from the eleventh thoracic vertebra to the second sacral vertebra. Common clinical presentations included lower back pain or soreness. Histologically, the tumors exhibited similar features characterized by papillary structures comprised of radiating cuboidal or elongated epithelioid glial tumor cells, encircling fibrovascular cores exhibiting transparent stromal changes. The interstitium showcased a mucinous appearance. Immunohistochemical analysis revealed expression of GFAP in all cases, while S-100 and CD56 were expressed in three cases. The Ki-67 index ranged from 1% to 5% across the four cases. NGS confirmed TERT C250T mutation in two case. Conclusions Multifocal myxopapillary ependymoma emerges as a rare variant of spinal cord tumor, with only 15 reported cases in the existing literature. Currently classified as grade 2 by the World Health Organization (WHO), most instances can be effectively managed through complete surgical resection, yielding favorable prognoses. However, compared to single-focus MPE, multifocal MPE exhibits a heightened propensity for recurrence and intraspinal dissemination.