Boo K, Cheng S
Department of Pathology, Faculty of Medicine, University of Malaya, Kuala Lumpur.
Malays J Pathol. 1992 Jun;14(1):45-8.
Monoclonal plasma cell proliferative diseases such as multiple myeloma and plasmacytoma can involve extramedullary sites at the time of first presentation, or subsequently in the course of the disease. Under such circumstances, they can mimic primary or metastatic carcinomas, neuroendocrine or neuroectodermal tumours and lymphomas, and the pathologist often has to resort to immunohistochemistry as an aid to diagnosis. We studied the morphology and immunohistochemical properties of 10 cases of previously confirmed monoclonal plasma cell proliferative lesions retrieved from the files of the Department of Pathology, University of Malaya. Serial 4u thick paraffin sections were stained with H&E, the Unna-Pappenheim technique for nucleic acid and a panel of antibodies using a standard immunoperoxidase technique. Light chain restriction was demonstrable in most of the cases. Seven (70%) showed kappa and 2 (20%) lambda light chain restriction. The remaining case was not stainable with most of the antibodies in the panel. The majority (80%) of cases showed accompanying IgG heavy chain in the cytoplasm, while 1 case had IgA. Seven (70%) showed membrane positivity with antibody to epithelial membrane antigen (EMA) and 7 (70%) cytoplasmic positivity with antibody to vimentin. This study enhances our awareness that neoplastic plasma cells can be positive for EMA and vimentin, and cautions us from misinterpreting these lesions as carcinomas or sarcomas. Notwithstanding that, immunohistochemical staining for kappa and lambda light chains can be helpful in differentiating monoclonal plasma cell proliferations from polyclonal ones.
单克隆浆细胞增殖性疾病，如多发性骨髓瘤和浆细胞瘤，在初次就诊时或疾病过程中可能累及髓外部位。在这种情况下，它们可能类似原发性或转移性癌、神经内分泌或神经外胚层肿瘤以及淋巴瘤，病理学家常常不得不借助免疫组织化学来辅助诊断。我们研究了从马来亚大学病理学系存档中检索出的10例先前确诊的单克隆浆细胞增殖性病变的形态学和免疫组织化学特性。连续4微米厚的石蜡切片用苏木精和伊红染色、用于核酸的Unna-Pappenheim技术以及使用标准免疫过氧化物酶技术的一组抗体进行染色。在大多数病例中可显示轻链限制。7例（70%）显示κ轻链限制，2例（20%）显示λ轻链限制。其余病例对该组中的大多数抗体均无染色反应。大多数病例（80%）在细胞质中显示伴随的IgG重链，而1例有IgA。7例（70%）对上皮膜抗原（EMA）抗体呈膜阳性，7例（70%）对波形蛋白抗体呈细胞质阳性。本研究提高了我们对肿瘤性浆细胞可对EMA和波形蛋白呈阳性的认识，并提醒我们不要将这些病变误诊为癌或肉瘤。尽管如此，κ和λ轻链的免疫组织化学染色有助于区分单克隆浆细胞增殖和多克隆浆细胞增殖。
