恶性小细胞肿瘤的免疫组化分析

目的 探讨不同组织来源的恶性小细胞肿瘤特殊染色、免疫组织化学染色特征，以提高恶性小细胞肿瘤诊断的准确性。方法 应用免疫组织化学方法检测26例恶性小细胞肿瘤，观察其对检测标记的反应。结果 26例中小细胞癌占6例，HE特点为核染色质密集，染色很深，核仁不明显，多伴坏死；免疫组织化学染色表明CK、EMA具有明显特异性。结外非何杰金氏淋巴瘤6例，LCA均为阳性，1例CK部分阳性，其余标记均为有性。滑膜肉瘤4例，Vim、EMA阳性，部分瘤细胞（小多边形细胞）CK阳性。血管外皮瘤3例，部分瘤细胞SMA阳性。横纹肌肉瘤2例，MG、MSA阳性。Ewing肉瘤2例，Vim、CD99（Mic2)阳性。小细胞骨肉瘤－Ewing瘤样型1例，Vim阳性。神经母细胞瘤1例，NSE、CHG－A阳性。恶性间皮瘤1例，CEA阳性。结论 免疫组织化学标记对大部分小细胞恶性肿瘤有较明显的特异性，尤其对小细胞癌与间叶源性小细胞肿瘤间的鉴别。但间叶源性和／或起源未定的小细胞肿瘤间仅凭免疫组织化学反应尚难以准确诊断，还需仔细寻找HE形态特点，结合组织化学、电镜检查，必须时做遗传学和基因学诊断。

Immunohistochemical Study of Malignant Small Cell Tumors

Objective To investigate special stain and immunohistochemical stain features of malignant small cell tumors from different origin to improve accurate diagnosis. Methods Twenty\|six cases with malignant small cell tumor were studied by means of immunochemical and histochemical stain. The reactions to the marked target were observed.Results In the 6 cases with small cell carcinomas, the presentation by HE stain was: hyperstained nuclei, vague nucleoli and necrosis of tumor cells. Immunohistochemical stain showed CK and EMA had obvious specificity. In the 6 cases with nonnodule and non\|Hodgkin's lymphoma, all were positive for LCA; one was partially positive for CK and the rest of markers were negative. In the 4 cases with synovial sarcoma, Vim and EMA were positive in all cases and CK was positive in some tumor cells (small multiform cells). In the 3 cases with hemangiopericytoma, some tumor cells were positive for SMA. MG and MSA were positive in the 2 cases with rhabdomyosarcoma. Vim and CD99(Mic2) were positive in the 2 cases with sarcoma\|Ewing. Vim was positive in 1 case with small cell osteosarcoma\|Ewing\|like. NSE and CHG\|A were positive in 1 case with neroblastoma. CEA was positive in 1 case with malignant mesothelioma. Conclusion Immunohistochemical method has specialties for most of the malignant small cell tumor, especially for deferential diagnosis between small cell carcinoma and small cell tumors which originated from mesenchyme. But it is difficult to make accurate diagnosis only by immunohistochemical method for tumors from mesenchyme and/or tumors whose origination was not clear. The diagnosis should be made by specific features in HE stain and combined with histochemical, electron microscopy, even genetics and gene diagnosis if necessary.