Bailey D, Baumal R, Marks A
Department of Pathology, Toronto General Hospital.
APMIS. 1988 Mar;96(3):206-10. doi: 10.1111/j.1699-0463.1988.tb05292.x.
Chest x-ray in a 20-year-old man showed a large anterior mediastinal mass and a needle aspirate was diagnosed by light microscopy (LM) as non-Hodgkin's lymphoma. Treatment with CHOP (cyclophosphamide, adriamycin, vincristine and prednisone) was ineffective and a tissue biopsy was performed. LM showed large, non-cohesive cells with abundant cytoplasm and rounded nuclei. Differential diagnoses included malignant lymphoma, seminoma, thymoma, anaplastic carcinoma, malignant melanoma and paraganglioma. Electron microscopy was not conclusive and immunoperoxidase staining was carried out. The malignant cells were negative for common leukocyte antigen, Leu M1, alpha-fetoprotein, chorionic gonadotrophin, cytokeratin, epithelial membrane antigen, carcinoembryonic antigen, S-100 protein and neuron-specific enolase but positive for placental alkaline phosphatase. In addition, there was strong positivity with a monoclonal antibody (mAb) which was recently shown to react with testicular seminomas. This case illustrates the value of this mAb in confirming the diagnosis of mediastinal seminoma.
一名20岁男性的胸部X光显示前纵隔有一个大肿块，针吸活检经光学显微镜检查诊断为非霍奇金淋巴瘤。采用CHOP方案（环磷酰胺、阿霉素、长春新碱和泼尼松）治疗无效，遂进行组织活检。光学显微镜检查显示细胞大，无黏附性，细胞质丰富，细胞核呈圆形。鉴别诊断包括恶性淋巴瘤、精原细胞瘤、胸腺瘤、间变性癌、恶性黑色素瘤和副神经节瘤。电子显微镜检查结果不明确，于是进行了免疫过氧化物酶染色。恶性细胞对常见白细胞抗原、Leu M1、甲胎蛋白、绒毛膜促性腺激素、细胞角蛋白、上皮膜抗原、癌胚抗原、S-100蛋白和神经元特异性烯醇化酶呈阴性，但对胎盘碱性磷酸酶呈阳性。此外，一种单克隆抗体呈强阳性，最近研究表明该抗体可与睾丸精原细胞瘤发生反应。该病例说明了这种单克隆抗体在确诊纵隔精原细胞瘤方面的价值。
