Kanno Hiroshi, Kanetsuna Yukiko, Shinonaga Masamichi
Department of Neurosurgery, International University of Health and Welfare Atami Hospital, Atami 413-0012, Shizuoka, Japan.
Department of Pathology, International University of Health and Welfare Atami Hospital, Atami 413-0012, Shizuoka, Japan.
World J Clin Oncol. 2021 Nov 24;12(11):1072-1082. doi: 10.5306/wjco.v12.i11.1072.
Myxopapillary ependymoma (MPE) is a pathological grade I tumor that arises in the filum terminale. MPE with anaplastic features is extremely rare, and only 5 cases have shown malignancy at the time of recurrence.
The patient (a 46-year-old woman) had undergone a MPE operation 30 years ago. After subtotal resection of the tumor located in L4-S1, it had a solid component that extended to the adjacent subcutaneous region. Histologically, the tumor consisted of a typical MPE with anaplastic features. The anaplastic areas of the tumor showed hypercellularity, a rapid mitotic rate, vascular proliferation, and connective tissue proliferation. Pleomorphic cells and atypical mitotic figures were occasionally observed. The MIB-1 index in this area was 12.3%. The immunohistochemical study showed immunoreactivity for vimentin, glial fibrillary acidic protein and S100. The morphological pattern and immunohistochemical profile were consistent with anaplastic MPE. The patient tolerated surgery well without new neurological deficits. She underwent local irradiation for the residual tumor and rehabilitation.
Although extremely rare, anaplastic MPE occurs in both pediatric and adult patients, similar to other ependymomas. At a minimum, close monitoring is recommended, given concerns about aggressive biological potential. In the future, further study is needed to determine the WHO classification criteria and genetic indicators of tumor progression. The possibility of malignant transformation of MPE should be taken into account, and patients with MPE should be treated with care and follow-up.
黏液乳头型室管膜瘤（MPE）是一种发生于终丝的I级病理肿瘤。具有间变特征的MPE极为罕见，仅有5例在复发时表现为恶性。
该患者（一名46岁女性）30年前接受过MPE手术。在对位于L4-S1的肿瘤进行次全切除后，发现肿瘤有一个实性成分延伸至邻近的皮下区域。组织学检查显示，肿瘤由具有间变特征的典型MPE组成。肿瘤的间变区域表现为细胞增多、有丝分裂率高、血管增生和结缔组织增生。偶尔可见多形性细胞和非典型有丝分裂象。该区域的MIB-1指数为12.3%。免疫组化研究显示波形蛋白、胶质纤维酸性蛋白和S100呈免疫反应性。形态学模式和免疫组化特征与间变性MPE一致。患者对手术耐受良好，未出现新的神经功能缺损。她接受了残留肿瘤的局部放疗和康复治疗。
尽管极为罕见，但间变性MPE在儿童和成人患者中均有发生，与其他室管膜瘤相似。鉴于其具有侵袭性生物学潜能，至少建议密切监测。未来，需要进一步研究以确定WHO分类标准和肿瘤进展的基因指标。应考虑MPE发生恶性转化的可能性，对MPE患者应谨慎治疗并进行随访。
