Himstead Alexander S, Perez-Rosendahl Mari, Fote Gianna M, Zhang Angie, Kim Michael G, Floriolli David, Quezado Martha, Aldape Kenneth, Pratt Drew, Abdullaev Zied, Monuki Edwin S, Hsu Frank P K, Yong William H
Department of Neurosurgery, University of California, Irvine School of Medicine, Orange, CA, USA.
Department of Pathology and Laboratory Medicine, University of California, Irvine School of Medicine, Orange, CA, USA.
Free Neuropathol. 2022 Jul 8;3:16. doi: 10.17879/freeneuropathology-2022-4076. eCollection 2022 Jan.
Ependymomas have rarely been described to contain pigment other than melanin, neuromelanin, lipofuscin or a combination. In this case report, we present a pigmented ependymoma in the fourth ventricle of an adult patient and review 16 additional cases of pigmented ependymoma from the literature. A 46-year-old female showed up with hearing loss, headaches, and nausea. Magnetic resonance imaging revealed a 2.5 cm contrast-enhancing cystic mass in the fourth ventricle, which was resected. Intraoperatively, the tumor appeared grey-brown, cystic, and was adherent to the brainstem. Routine histology revealed a tumor with true rosettes, perivascular pseudorosettes and ependymal canals consistent with ependymoma, but also showed chronic inflammation and abundant distended pigmented tumor cells that mimicked macrophages in frozen and permanent sections. The pigmented cells were positive for GFAP and negative for CD163 consonant with glial tumor cells. The pigment was negative for Fontana-Masson, positive for Periodic-acid Schiff and autofluorescent, which coincide with characteristics of lipofuscin. Proliferation indices were low and H3K27me3 showed partial loss. H3K27me 3 is an epigenetic modification to the DNA packaging protein Histone H3 that indicates the tri-methylation of lysine 27 on histone H3 protein. This methylation classification was compatible with a posterior fossa group B ependymoma (EPN_PFB). The patient was clinically well without recurrence at three-month post-operative follow-up appointment. Our analysis of all 17 cases, including the one presented, shows that pigmented ependymomas are most common in the middle-aged with a median age of 42 years and most have a favorable outcome. However, one patient that also developed secondary leptomeningeal melanin accumulations died. Most (58.8%) arise in the 4th ventricle, while spinal cord (17.6%) and supratentorial locations (17.6%) were less common. The age of presentation and generally good prognosis raise the question of whether most other posterior fossa pigmented ependymomas may also fall into the EPN_PFB group, but additional study is required to address that question.
室管膜瘤很少被描述为含有除黑色素、神经黑色素、脂褐素或其组合之外的色素。在本病例报告中，我们展示了一名成年患者第四脑室内的色素沉着室管膜瘤，并回顾了文献中另外16例色素沉着室管膜瘤病例。一名46岁女性出现听力丧失、头痛和恶心症状。磁共振成像显示第四脑室内有一个2.5厘米的强化囊性肿块，该肿块被切除。术中，肿瘤呈灰棕色，囊性，与脑干粘连。常规组织学检查显示肿瘤有真性菊形团、血管周围假菊形团和室管膜管，符合室管膜瘤特征，但也显示慢性炎症以及大量肿胀的色素沉着肿瘤细胞，在冰冻切片和永久切片中类似巨噬细胞。色素沉着细胞GFAP呈阳性，CD163呈阴性，与胶质肿瘤细胞一致。色素对Fontana-Masson染色呈阴性，对过碘酸希夫染色呈阳性且自发荧光，这与脂褐素的特征相符。增殖指数较低，H3K27me3显示部分缺失。H3K27me3是对DNA包装蛋白组蛋白H3的一种表观遗传修饰，表明组蛋白H3蛋白赖氨酸27的三甲基化。这种甲基化分类与后颅窝B组室管膜瘤（EPN_PFB）相符。术后三个月随访时，患者临床状况良好，无复发。我们对包括本病例在内的所有17例病例的分析表明，色素沉着室管膜瘤在中年人中最为常见，中位年龄为42岁，大多数预后良好。然而，有一名患者还出现了继发性软脑膜黑色素沉着并死亡。大多数（58.8%）发生在第四脑室中，而脊髓（17.6%）和幕上部位（17.6%）则较少见。发病年龄和总体良好的预后引发了一个问题，即大多数其他后颅窝色素沉着室管膜瘤是否也可能属于EPN_PFB组，但需要进一步研究来解决这个问题。
