We report a case of 33-year-old Japanese male who presented with a headache and visual disturbances. Magnetic resonance imaging revealed a large tumor in the left frontal lobe, measuring 7 cm in diameter, which was diagnosed as supratentorial anaplastic ependymoma accompanied by extensive desmoplasia. The patient underwent a gross total resection. Histologically, the tumor cells had oval or short, spindle-shaped nuclei, and proliferating cells in perivascular pseudorosettes with anucleate zones and mitotic figures. Desmoplasia with abundant collagen fibers among the tumor cells was detected at numerous sites, and perinuclear dot- or ring-like immunoreactivity for epithelial membrane antigen was identified. Five years and six months after the initial procedure, a small recurrent tumor was identified at the removal site. The patient underwent a second total resection. The histology of the resected tumor showed decreased collagen production and more apparent anaplastic features as compared to those of the initial tumor. In addition to the histological findings, molecular examinations revealed ependymoma, RELA fusion positive. Although not commonly observed, this case suggests that desmoplasia could be associated with ependymomas, including RELA fusion-positive variant. Moreover, our findings indicate that high-grade ependymoma requires careful, long-term follow-up even if gross total resection is performed.

我们报告一例33岁的日本男性，出现头痛和视力障碍。磁共振成像显示左额叶上有一个大肿瘤，直径为7厘米，被诊断为幕上性间变性室间隔膜瘤，并伴有广泛的异型增生。病人接受了全切除术。从组织学上看，肿瘤细胞在椭圆形或短的纺锤形细胞核中，并在具有无核带和有丝分裂像的血管周假红斑中增生。在许多部位检测到肿瘤细胞中胶原纤维丰富的异型增生，并鉴定了对上皮膜抗原的核周点或环状免疫反应性。初始手术后五年零六个月，在切除部位发现了一个小的复发性肿瘤。病人进行了第二次全切除。与最初的肿瘤相比，切除的肿瘤的组织学显示胶原蛋白的产生减少和更明显的变性特征。除了组织学检查结果外，分子检查还发现室管膜瘤，RELA融合阳性。尽管不常见，但这种情况表明，发育不全可能与室间隔膜瘤相关，包括RELA融合阳性变体。此外，我们的研究结果表明，即使进行了总的全切除术，高级别的室管膜瘤也需要仔细的长期随访。