Adult Langerhans cell histiocytosis (LCH) remains poorly defined. We retrospectively studied 266 newly diagnosed LCH patients to understand the clinical presentation, treatment, and prognosis of adult LCH. The median age at diagnosis was 32 years (range, 18–79 years). At the time of diagnosis, 40 patients had single lesions within a single system, 18 patients had single pulmonary LCH, 26 patients had multiple lesions within a single system (SS-m), and 182 patients had multisystem disease (MS). The most common organ involved in MS patients was the bone (69.8%), followed by the pituitary (61.5%) and lung (61.0%). BRAF^V600E, BRAF deletion, and MAP2K1 mutation were detected in 38.8%, 25.4%, and 19.4% patients, respectively. BRAF deletion was found more common in patients with MS LCH compared to single-system LCH (38.5% vs 7.1%, p = .004), also in patients with liver involvement (69.2% vs 14.3%, p < .001). The estimated 3-year overall survival (OS) and event-free survival (EFS) rates were 94.4% and 54.7%, respectively, in SS-m and MS LCH. Multivariate Cox regression showed that involvement of the liver or spleen at baseline predicted poor EFS and receiving cytarabine-based therapy as a first-line treatment and age older than 30 years at diagnosis predicted favorable EFS. The involvement of risk organs and age older than 50 years predicted poor OS, and receiving cytarabine-based therapy predicted favorable OS. Therefore, BRAF deletion was correlated with MS LCH, particularly those with liver involvement. Liver or spleen involvement at baseline indicates a poor prognosis, and a cytarabine-based regimen could be considered as first-line treatment for adult LCH patients.

中文翻译：

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成人朗格汉斯细胞组织细胞增多症患者的治疗结果及预后因素

成人朗格汉斯细胞组织细胞增生症 (LCH) 的定义仍然不明确。我们回顾性研究了 266 例新诊断的 LCH 患者，以了解成人 LCH 的临床表现、治疗和预后。诊断时的中位年龄为 32 岁（范围为 18-79 岁）。诊断时，40例患者单系统内单一病变，18例患者单肺LCH，26例患者单系统内多病变（SS-m），182例患者多系统病变（MS）。MS 患者最常见的器官是骨骼（69.8%），其次是垂体（61.5%）和肺（61.0%）。BRAF ^V600E、BRAF缺失和MAP2K1突变分别在 38.8%、25.4% 和 19.4% 的患者中检测到。布拉夫与单系统 LCH 相比，MS LCH 患者的缺失更常见（38.5% 对 7.1%，p  = .004），肝脏受累患者也有（69.2% 对 14.3%，p  < .001）。在 SS-m 和 MS LCH 中，估计的 3 年总生存期 (OS) 和无事件生存期 (EFS) 率分别为 94.4% 和 54.7%。多变量 Cox 回归显示，基线时肝脏或脾脏受累预测 EFS 较差，接受基于阿糖胞苷的治疗作为一线治疗，诊断时年龄超过 30 岁预测良好的 EFS。风险器官受累和年龄超过 50 岁预示着较差的 OS，而接受基于阿糖胞苷的治疗则预示着有利的 OS。因此，BRAF缺失与 MS LCH 相关，尤其是肝脏受累的患者。基线时肝脏或脾脏受累表明预后不良，基于阿糖胞苷的方案可被视为成人 LCH 患者的一线治疗。