[Clinicopathological and molecular features of Erdheim-Chester disease accompanied with Langerhans cell histiocytosis].

Objective: To investigate the clinicpathological and molecular features of Erdheim-Chester disease (ECD) as well langerhans cell histiocytosis (LCH). Methods: The clinical, histopathological, molecular findings, immunophenotype, treatment and prognosis in 4 cases of ECD combined LCH were evaluated from February 2015 to September 2018 with review of the relevant literature. Results: 2 cases were male, and 2 were female, aged from 7-55 years. Microscopically, there were two different areas, in the first area, the lesions were composed of foamy histiocytes, spindle-shaped fibroblasts, scattered multinucleated giant cells. Lymphocytes, plasma cells, and giant cells were also found. In the other, the lesions were composed of histiocytes with obvious nuclear groove, associated with a variable number of eosinophils, lymphocytes and plasma cells. Immunephenotype, In the second area, histiocytes were positive for CD1a (4/4), S-100 (4/4),CD207/Langerin (4/4), cyclin D1(4/4), and in the two different area, the histiocytes were positive for CD68, CD163, Braf. Ki-67 positive index 1%-10% BRAF V600E gene mutation was detected in three cases. Conclusion: ECD combined LCH was a very rare histiocytosis tumor and its correct diagnosis relies on histopathologic features, immunohistochemical staining, and BRAF V600E gene detection.目的： 探讨Erdheim-Chester病（ECD）合并朗格汉斯细胞组织细胞增生症（LCH）的临床病理学特征、免疫组织化学及BRAF V600E基因突变状态。 方法： 收集北京协和医院2015年2月至2018年9月诊断的4例ECD合并LCH进行组织形态学、免疫组织化学及BRAF V600E基因检测，并随访及复习相关文献。 结果： 男性2例，女性2例，发病年龄7~55岁（平均32.5岁）。病理组织学：病变有两种区域，一是病变细胞呈泡沫样组织细胞样，伴有纤维母细胞增生，可见散在分布的多核巨细胞，间质炎性细胞浸润，二是组织细胞浸润，可见核沟，间质见较多嗜酸性粒细胞浸润。免疫表型：第二种区域细胞呈S-100蛋白、CD1a、CD207/Langerin、cyclin D1阳性；2种区域细胞共同阳性表达CD68、CD163、Braf。Ki-67阳性指数约为1%~10%。分子病理检测：3例（3/4）检测到BRAF V600E基因突变。 结论： ECD合并LCH属于罕见的组织细胞发生的肿瘤，具有一定的组织学特征。诊断主要依靠影像学、病理形态学、免疫组织化学标记及BRAF V600E基因检测。.