肺炎性平滑肌肉肉瘤（PILMS）是一种罕见的肌肉源性肿瘤，具有显著的淋巴组织细胞浸润。尽管在组织学上相似，但PILMS在免疫组织化学和遗传学上与软组织炎性平滑肌肉肉瘤有所不同，其临床病理图片，包括DNA甲基化组学数据仍然未知。在这里，我们报道了一例18岁男性患者的PILMS病例，该患者接受了肺叶切除术。如先前报告的那样，当前病例显示了在显著的淋巴组织细胞浸润中螺纹肌样细胞增殖和平滑肌分化，以及一个二倍体基因组和MUC3A基因改变。DNA甲基化分析根据德国癌症研究中心（DKFZ）分类器预测该病例为“炎性肌成纤维瘤”（IMT）。数据经t分布随机邻域嵌入分析，将该病例肿瘤点绘制在IMT附近，然而，没有IMT的组织学特征。这些不一致的结果可能是由于背景非肿瘤性炎症细胞引起的。鉴于PILMS的DNA甲基化分类可能是一种潜在的诊断陷阱，需要综合组织学和遗传学方法进行准确诊断。 © 2023年 BioMed Central有限公司，Springer Nature的一部分。

Pulmonary inflammatory leiomyosarcoma (PILMS) is a rare type of myogenic tumor with prominent lymphohistiocytic infiltration. Despite their histological similarities, PILMS is immunohistochemically and genetically distinct from soft tissue inflammatory leiomyosarcoma, and its clinicopathological picture including DNA methylome data remains still unknown.Here we present a case of PILMS in an 18-year-old male who underwent lobectomy. As reported previously, the current case demonstrated spindle myoid cell proliferation with smooth muscle differentiation within a prominent lymphohistiocytic infiltration and a diploid genome with a MUC3A gene alteration. DNA methylation analysis predicted this case to be an "inflammatory myofibroblastic tumor" (IMT) according to the Deutsches Krebsforschungszentrum (DKFZ) classifier. The data was analyzed by t-distributed stochastic neighbor embedding, which plotted the case tumor in the vicinity of IMT, however, there were no IMT histological features. These discordant results could be due to background non-neoplastic inflammatory cells.As the DNA methylation classification of PILMS might be a potential diagnostic pitfall, an integrative histological and genetic approach is required for its accurate diagnosis.© 2023. BioMed Central Ltd., part of Springer Nature.