Abstract：
Langerhans cell histiocytosis (LCH) is a neoplastic condition of Langerhans cells, and can be associated with other neoplasms, especially BRAF-mutant hematological tumors and papillary thyroid carcinoma. Here we present the first case of co-existing LCH and low cumulative sun damage (low-CSD) melanoma, both of which had a BRAF V600E mutation. A 49-year-old man had a 45 × 43 × 15 mm semi-pedunculated, pigmented tumor in his back but had no other systemic symptoms. Histopathology revealed a 2-mm-sized incidental focus of LCH within a large lesion of low-CSD melanoma. Diffuse immunoexpression of CD1a, langerin/CD207, S100 protein, and BRAF (VE1) was observed in the focus of LCH. Sanger sequencing with microdissection confirmed BRAF V600E mutation in the component of LCH. Interestingly, the advanced melanoma also harbored the same BRAF V600E mutation, although the significance of this tumor combination is still unknown.
摘要：
朗格汉斯细胞组织细胞增生症（LCH）是朗格汉斯细胞的肿瘤，并可能与其他肿瘤有关，尤其是BRAF突变的血液肿瘤和甲状腺乳头状癌。在这里，我们介绍了第一例共存的LCH和低累积阳光损伤（低CSD）黑色素瘤，两者都有一个BRAFV600E突变。一名49岁的男子有一个45×43×15毫米的半花梗，他的背部有色素性肿瘤，但没有其他全身症状。组织病理学显示，在低CSD黑色素瘤的大病灶内，有2毫米大小的LCH偶然病灶。CD1a的弥漫性免疫表达，langerin/CD207,S100蛋白,在LCH的病灶中观察到BRAF（VE1）。具有显微切割的Sanger测序证实了LCH组分中的BRAFV600E突变。有趣的是,晚期黑色素瘤也带有相同的BRAFV600E突变，尽管这种肿瘤组合的意义仍然未知。
