Scheck O, Ruck P, Harms D, Kaiserling E
Institute of Pathology, Eberhard-Karls University, Tübingen, Federal Republic of Germany.
Ultrastruct Pathol. 1989 Jan-Feb;13(1):23-33. doi: 10.3109/01913128909051157.
We report an exceptional case of melanotic neuroectodermal tumor of infancy (MNTI) occurring in the soft tissue of the left thigh of a 6-month-old female infant. The tumor consisted mainly of small round cells (neuroblasts) arranged in cords and nests that were separated by broad fibrovascular areas. In addition, there were a few medium-sized tumor cells containing melanin pigment (melanocytic cells) that in electron microscopy contained melanosomes as well as tonofilaments. Both tumor cell types immunostained for neuron-specific enolase (NSE) and vimentin, and the melanocytic cells reacted additionally with the antikeratin antibody KL1. Within the tumor stroma, neurofilament- and S-100-protein-positive neural cells and vimentin- and desmin-positive myofibroblasts were seen. Although dense-core granules were demonstrated ultrastructurally in some neuroblasts, no immunostaining for chromogranin A, Leu-7, serotonin, or regulatory peptides was found. MNTI located in an extremity can be confused with malignant small round and blue cell tumors of childhood. The distinction between MNTI and these tumors is of clinical significance because MNTI, in most cases, is a benign tumor that, in contrast to the latter, can be cured by complete excision. The presence of a biphasic cell population with neuroblasts and melanocytic cells must be considered the main diagnostic feature of MNTI.
我们报告了一例罕见的婴儿黑素性神经外胚层肿瘤（MNTI），发生于一名6个月大女婴的左大腿软组织。肿瘤主要由排列成条索状和巢状的小圆形细胞（神经母细胞）组成，这些细胞被宽阔的纤维血管区域分隔。此外，有少数含黑色素的中等大小肿瘤细胞（黑素细胞），电镜下可见其含有黑素小体和张力丝。两种肿瘤细胞类型均对神经元特异性烯醇化酶（NSE）和波形蛋白呈免疫反应，黑素细胞还与抗角蛋白抗体KL1发生反应。在肿瘤基质中，可见神经丝和S-100蛋白阳性的神经细胞以及波形蛋白和平滑肌肌动蛋白阳性的肌成纤维细胞。虽然在一些神经母细胞中电镜下显示有致密核心颗粒，但未发现嗜铬粒蛋白A、Leu-7、5-羟色胺或调节肽的免疫染色。位于四肢的MNTI可能会与儿童期恶性小圆形蓝细胞肿瘤相混淆。MNTI与这些肿瘤的鉴别具有临床意义，因为在大多数情况下，MNTI是一种良性肿瘤，与后者不同，通过完整切除即可治愈。具有神经母细胞和黑素细胞的双相细胞群的存在必须被视为MNTI的主要诊断特征。
