Suster S, Moran C A
Arkadi M. Rywlin Department of Pathology and Laboratory Medicine, University of Miami, FL, USA.
Hum Pathol. 1995 Dec;26(12):1354-62. doi: 10.1016/0046-8177(95)90301-1.
Six cases of chordomas presenting as primary posterior mediastinal tumors are described. Three patients were female, and three were male between the ages of 8 and 65 years (mean, 40.6 years). In all cases, the tumors presented radiographically as relatively well-circumscribed, encapsulated soft tissue masses that did not seem to be related to the thoracic or dorsal spine. Only in one case, focal infiltration of bone at the level of T6-T7 was observed at the time of surgery. Histologically, the lesions showed a spectrum of features that ranged from sheets and cords of large cells with abundant vacuolated cytoplasm to small, stellate cells embedded within an abundant mucoid matrix. In one case, the cell population showed more pronounced nuclear atypia with loss of cytoplasmic vacuolization, frequent mitotic figures, necrosis, and solid areas characterized by a perivascular distribution of atypical spindle cells set against a myxoid stroma. Another case showed features of chondroid chordoma, with an immature chondroid-appearing matrix surrounding the atypical tumor cells. Immunohistochemical studies in all cases showed positive staining of the tumor cells with CAM 5.2 and broad-spectrum keratin, epithelial membrane antigen (EMA) and vimentin, and, to a lesser extent, with S-100 protein. Stains for muscle actin, carcinoembryonic antigen (CEA), and desmin were negative. Ultrastructural examination in two cases showed a spectrum of features that varied from large cells with abundant cytoplasm containing scattered ribosomes, glycogen granules, Golgi apparatti, abundant intermediate filaments, and small lumen formation with immature microvilli to smaller cells with elongated cytoplasmic processes, fewer intermediate filaments, rare desmosome type intercellular junctions, and complexes of mitochondria/rough endoplasmic reticulum. On clinical follow-up, two patients died with metastases to the lungs, chest wall, and liver from 1 to 3 years after diagnosis, and two patients are alive and well without evidence of disease after 3 and 16 years. Chordoma should be entertained in the differential diagnosis of posterior mediastinal tumors. Application of immunohistochemical stains or electron microscopy will be of aid in separating them from other conditions that may histologically closely resemble these lesions.
本文描述了6例表现为原发性后纵隔肿瘤的脊索瘤病例。3例为女性，3例为男性，年龄在8至65岁之间（平均40.6岁）。在所有病例中，肿瘤在影像学上表现为边界相对清晰、有包膜的软组织肿块，似乎与胸椎或背柱无关。仅在1例中，手术时观察到T6 - T7水平的骨局灶性浸润。组织学上，病变表现出一系列特征，从具有丰富空泡状细胞质的大细胞片和索状结构到嵌入丰富黏液样基质中的小星状细胞。在1例中，细胞群体显示出更明显的核异型性，伴有细胞质空泡化丧失、频繁的有丝分裂象、坏死，以及以非典型梭形细胞围绕黏液样基质呈血管周围分布为特征的实性区域。另一例显示软骨样脊索瘤的特征，非典型肿瘤细胞周围有不成熟的软骨样基质。所有病例的免疫组织化学研究显示肿瘤细胞对CAM 5.2、广谱角蛋白、上皮膜抗原（EMA）和波形蛋白呈阳性染色，对S - 100蛋白的染色程度较轻。肌肉肌动蛋白、癌胚抗原（CEA）和结蛋白染色均为阴性。2例的超微结构检查显示出一系列特征，从具有丰富细胞质的大细胞，含有散在核糖体、糖原颗粒、高尔基体、丰富中间丝，以及形成带有不成熟微绒毛的小腔，到具有细长细胞质突起、较少中间丝、罕见桥粒型细胞间连接，以及线粒体/粗面内质网复合体的较小细胞。临床随访中，2例患者在诊断后1至3年死于肺、胸壁和肝转移，2例患者在3年和16年后存活且状况良好，无疾病证据。在鉴别诊断后纵隔肿瘤时应考虑脊索瘤。应用免疫组织化学染色或电子显微镜有助于将它们与其他在组织学上可能与这些病变非常相似的疾病区分开来。
