四肢原发性胚胎性横纹肌肉瘤的影像学表现及病理特征

目的探讨四肢原发性胚胎性横纹肌肉瘤的影像特点,以提高对此肿瘤的影像诊断水平。方法选取7例经病理证实的四肢原发性胚胎性横纹肌肉瘤的临床资料、病理结果及影像学表现。结果7例四肢原发性胚胎性横纹肌肉瘤中,2例原发于骨组织,5例原发于软组织,其中1例侵犯相邻骨质。位于骨组织者,X线平片示髓腔呈溶骨性骨质破坏,轻度膨胀,可见骨膜反应;MRI示肿瘤呈长T₁、长T₂信号改变,增强扫描病灶呈明显不均匀强化。位于软组织者,CT平扫示肿瘤边界清晰,增强扫描病灶轻度强化;MRI示肿瘤呈长T₁、长T₂信号改变,增强扫描病灶明显强化。结论四肢原发性胚胎性横纹肌肉瘤发病率低,临床症状与影像表现缺乏特异性,确诊依赖于细胞形态学与免疫组织化学检查。     

Heterogeneity in the immune microenvironment of bone metastasis in driver-positive non-small cell lung cancer

Mutations in epidermal growth factor receptor and anaplastic lymphoma kinase are common driver events in non-small cell lung cancer (NSCLC), which are associated with a high frequency of bone metastases (BMs). While the bone marrow represents a specialized immune microenvironment, the immune repertoire of BMs remains unknown. Considering the higher incidence of BMs in driver gene-positive NSCLCs, and the unique biology of the bone, herein, we assessed the infiltrating immune cells and T cell receptor (TCR) profile of BMs in driver-positive NSCLCs. Immune profile of BMs in driver gene-positive NSCLC were assessed in 10 patients, where 6 had driver gene-positive mutation. TCR and bulk RNA sequencing were performed on malignant bone samples. The diversity and clonality of the TCR repertoire were analyzed. The cellular components were inferred from bulk gene expression profiles computationally by CIBERSORT. Although BMs were generally regarded as immune-cold tumors, immune cell composition analyses showed co-existence of cytotoxic and suppressor immune cells in driver-positive BM samples, as compared to primary lung. Analysis of the TCR repertoire indicated a trend of higher diversity and similar clonality in the driver-positive compared with the driver-negative subsets. In addition, we identified two cases that showed the opposite response to immune checkpoint blockade. A comparison of these two patients' BM samples showed more highly amplified clones, fewer M2 macrophages and more activated natural killer cells in the responder. In summary, BMs in NSCLC are heterogeneous in their immune microenvironment, which might be related to differential clinical outcomes to immune checkpoint blockade.