Chai Yun, Woo Chang Gok, Kim Joo-Young, Kim Chong Jai, Khang Shin Kwang, Kim Jiyoon, Park In Ah, Kim Eun Na, Kim Kyu-Rae
Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
Department of Pathology, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon, Korea.
J Pathol Transl Med. 2017 Jan;51(1):49-55. doi: 10.4132/jptm.2016.09.19. Epub 2016 Oct 14.
Immature teratoma (IT) is a tumor containing immature neuroectodermal tissue, primarily in the form of neuroepithelial tubules. However, the diagnosis of tumors containing only cellular neuroglial tissue (CNT) without distinct neuroepithelial tubules is often difficult, since the histological characteristics of immature neuroectodermal tissues remain unclear. Here, we examined the significance of CNT and tried to define immature neuroectodermal tissues by comparing the histological features of neuroglial tissues between mature teratoma (MT) and IT.
The histological features of neuroglial tissue, including the cellularity, border between the neuroglial and adjacent tissues, cellular composition, mitotic index, Ki-67 proliferation rate, presence or absence of tissue necrosis, vascularity, and endothelial hyperplasia, were compared between 91 MT and 35 IT cases.
CNTs with a cellularity grade of ≥ 2 were observed in 96% of IT cases and 4% of MT cases (p < .001); however, CNT with a cellularity grade of 3 in MT cases was confined to the histologically distinct granular layer of mature cerebellar tissue. Moreover, CNT in IT exhibited significantly higher rates of Ki-67 proliferation, mitoses, and necrosis than those in MT (p < .001). Furthermore, an infiltrative border of neuroglial tissue and glomeruloid endothelial hyperplasia were significantly more frequent in IT cases than in MT cases (p < .001).
Our results suggest that if CNT with a cellularity grade of ≥ 2 is not a component of cerebellar tissue, such cases should be diagnosed as IT containing immature neuroectodermal tissue, particularly if they exhibit an infiltrative border, mitoses, necrosis, and increased Ki-67 proliferation.
未成熟畸胎瘤（IT）是一种包含未成熟神经外胚层组织的肿瘤，主要呈神经上皮小管的形式。然而，对于仅含有细胞性神经胶质组织（CNT）而无明显神经上皮小管的肿瘤，其诊断往往困难，因为未成熟神经外胚层组织的组织学特征仍不清楚。在此，我们通过比较成熟畸胎瘤（MT）和IT中神经胶质组织的组织学特征，研究了CNT的意义，并试图界定未成熟神经外胚层组织。
比较了91例MT和35例IT病例中神经胶质组织的组织学特征，包括细胞密度、神经胶质组织与相邻组织之间的边界、细胞组成、有丝分裂指数、Ki-67增殖率、组织坏死的有无、血管形成以及内皮细胞增生情况。
在96%的IT病例和4%的MT病例中观察到细胞密度分级≥2的CNT（p<0.001）；然而，MT病例中细胞密度分级为3的CNT局限于成熟小脑组织组织学上明显的颗粒层。此外，IT中的CNT比MT中的CNT表现出显著更高的Ki-67增殖率、有丝分裂率和坏死率（p<0.001）。此外，IT病例中神经胶质组织的浸润性边界和肾小球样内皮细胞增生明显比MT病例更常见（p<0.001）。
我们的结果表明，如果细胞密度分级≥2的CNT不是小脑组织的组成部分，此类病例应诊断为含有未成熟神经外胚层组织的IT，特别是如果它们表现出浸润性边界、有丝分裂、坏死和Ki-67增殖增加。
