BACKGROUND Cystic airspace is an uncommon imaging manifestation involved in non-small lung cancer (NSCLC). Diffuse cystic lesion is even rarer as pulmonary manifestation of NSCLC. In the present study, we reported a rare case of NSCLC associated with progressive diffusion of cystic lesions misdiagnosed as Pulmonary langerhans cell histocytosis (PLCH), finally diagnosed by transbronchial cryobiopsy (TBCB). CASE PRESENTATION A 52-year-old woman was admitted to our hospital due to cough and dyspnea. High-resolution computed tomography (HRCT) presented diffuse cystic shadow mostly, concomitantly with nodular densities in bilateral lungs. A lung biopsy revealed poorly differentiated adenocarcinoma with vascular tumor emboli. The epidermal growth factor receptor (EGFR) mutation on exon 18 (G719X, G719) was detected by mutation test. The patient received treatment of tyrosine kinase inhibitor (afatinib). CONCLUSIONS Diffuse cystic lesion can be a rare manifestation of lung cancer. It was important to improve the recognition of diffuse cystic lung diseases to avoid misdiagnosis.

中文翻译：

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患有弥漫性囊性病变的肺癌被误诊为肺部Langerhans细胞组织细胞增生症：1例报道。

背景技术囊性空域是一种涉及非小肺癌（NSCLC）的罕见影像学表现。弥漫性囊性病变甚至很少见于NSCLC的肺部表现。在本研究中，我们报道了少见的NSCLC病例，其与囊性病变的进行性扩散有关，被误诊为肺部Langerhans细胞组织细胞增生症（PLCH），最终通过经支气管冷冻检查（TBCB）进行诊断。病例介绍一名52岁的妇女因咳嗽和呼吸困难入院。高分辨率计算机断层扫描（HRCT）大多呈现弥漫性囊性阴影，并伴有双侧肺结节性密度。肺活检显示低分化腺癌伴血管瘤栓塞。通过突变测试检测外显子18（G719X，G719）上的表皮生长因子受体（EGFR）突变。该患者接受了酪氨酸激酶抑制剂（阿法替尼）的治疗。结论弥漫性囊性病变可能是肺癌的罕见表现。重要的是要提高对弥漫性囊性肺病的认识，以避免误诊。