Objective: To investigate the clinicopathological features, immunophenotype, differential diagnosis, molecular genetic changes and prognosis of salivary gland-type clear cell carcinoma (CCC) of the lung. Methods: Eight cases of salivary gland-type CCC of the lung diagnosed at Fudan University Shanghai Cancer Center and Shanghai Pulmonary Hospital, China from March 2017 to December 2020 were retrieved and analyzed. The pathological sections of these cases were studied using immunohistochemical staining, fluorescence in situ hybridization (FISH), and RNA-seq fusion gene detection based on next generation sequencing technique. The patients were followed up and the relevant literature was reviewed. Results: The 8 patients included 3 males and 5 females, with age ranging from 43 to 64 years (average, 58 years). All patients underwent radical lobectomy and lymph node dissection, while only one had lymph node metastases. The eight patients were followed up for 6 to 45 months, and were all recurrence-free. Histopathologically, the tumor was mainly composed of eosinophilic and clear cells arranged in trabecular, ribbon and nest patterns. Hyalinization was often observed in the stroma around the nest. Immunohistochemical staining showed that 8/8 cases were positive for EMA and CK7; 5/8 cases were positive for p63 and p40; 4/8 cases were positive for SOX10; and the cases were all negative for S-100, SMA and calponin. EWSR1 gene fusion was detected in all cases by FISH. RNA-seq fusion gene was detected in 6 cases based on next generation sequencing. The EWSR1-ATF1 gene fusion was detected in 5 cases, among which one case also had the ATF1-SPTLC2 gene fusion. All 5 cases with EWSR1-ATF1 gene fusion showed that EWSR1 exon 12/13 fused with ATF1 exon 3. And EWSR1-CREM gene fusion was detected in one case. Conclusions: Salivary gland-type CCC of the lung is an extremely rare primary lung tumor arising from the bronchial mucosa. The diagnosis and differential diagnosis of this tumor depend on classic histomorphology, especially the auxiliary detection of EWSR1 fusion gene. The primary treatment choice of this tumor is complete surgical resection. Lymph node metastases may occur, but the overall prognosis is good.
目的： 探讨肺原发涎腺型透明细胞癌的临床病理学特征、免疫表型、鉴别诊断、分子遗传学特征及预后。 方法： 收集2017年3月至2020年12月在复旦大学附属肿瘤医院和同济大学附属上海市肺科医院确诊的8例肺原发涎腺型透明细胞癌的临床病理资料，对标本进行免疫组织化学、荧光原位杂交（FISH）检测和基于二代测序技术的RNA-seq融合基因检测，随访患者并复习相关文献。 结果： 8例患者年龄43~64岁，平均58岁。男女比为3∶5。8例患者均行根治性肺叶切除加淋巴结清扫，1例发生淋巴结转移，术后随访6~45个月均无复发。组织病理学主要由排列呈小梁状、带状、巢状的嗜酸性细胞及透明细胞组成，细胞巢周围间质中常有玻璃样变物包绕。免疫表型：8例肿瘤细胞上皮细胞膜抗原（EMA）、细胞角蛋白（CK）7均呈阳性表达，5例p63、p40呈阳性表达，4例SOX10呈阳性表达，S-100蛋白、平滑肌肌动蛋白（SMA）、Calponin均呈阴性表达。8例FISH均检测出EWSR1融合基因。6例进行了基于二代测序技术的RNA-seq融合基因检测，5例检测到EWSR1-ATF1融合基因（其中1例同时有ATF1-SPTLC2融合基因），5例EWSR1-ATF1基因融合均显示EWSR1外显子12/13与ATF1外显子3融合。1例为EWSR1-CREM基因融合。 结论： 肺原发涎腺型透明细胞癌是一种罕见的起源于支气管黏膜的原发肺肿瘤，该肿瘤诊断和鉴别诊断依赖于特征性形态学表现，特别是EWSR1融合基因检测辅助诊断，治疗以手术完整切除为主，可以发生淋巴结转移，但总体预后较好。.