探讨SMARCA4缺失性非小细胞肺癌（SMARCA4-dNSCLC）的临床病理特征、分子遗传学特征及PD-L1表达、诊断及鉴别诊断。

回顾性分析安庆市立医院2017年1月至2023年3月诊断的8例SMARCA4-dNSCLC的临床病理学及免疫表型特征,采用二代测序技术分析分子遗传学特征。

8例全部为男性，患者年龄48~73岁，平均63岁。肿瘤均发生于单侧肺，直径2~7 cm。镜检：癌细胞呈上皮样，胞质丰富，嗜酸或透亮，细胞核空泡状，核仁明显，核分裂象易见，排列呈片状、岛状或腺泡状，伴地图状坏死。局灶癌细胞失黏附，呈横纹肌样。免疫表型：SMARCA4蛋白（BRG1）（7/8）阴性，（1/8）部分阳性。5例NGS检测：1例存在TP53及ERBB2突变，1例存在TP53突变及NRAS微量突变，1例存在TP53突变，1例存在RET体细胞错义突变，1例未发现基因突变。5例检测PD-L1蛋白，1例阴性，3例表达，1例高表达。全部病例行肺叶切除手术，1例术前辅助化疗，5例术后辅助治疗，随访时间1~67个月。7例患者获得随访, 6例无瘤生存，1例出现远处转移。

SMARCA4-dNSCLC是一组临床病理特征独特，具有特殊的免疫组化表达，缺乏常见靶向药物基因突变，PD-L1高阳性率的肺罕见恶性肿瘤。

To explore the clinicopathological and molecular characteristics, programmed cell death 1 ligand 1 (PD-L1) expression, and diagnosis and differential diagnosis of SMARCA4-deficient non-small cell lung cancer (SMARCA4-dNSCLC).

The clinical morphological and immunohistochemical features of 8 cases of SMARCA4-dNSCLC diagnosed at Anqing Municipal Hospital from January 2017 to March 2023 were retrospectively analyzed, and the molecular genetic features of five cases were studied using next generation sequencing technique (NGS).

All of the 8 patients were male, aged from 48 to 73 years (mean 63 years). The tumors were located in unilateral lung and ranged from 2 to 7 cm in diameter. Microscopically, the tumor cells were epithelioid and rich in acidophilic or translucent cytoplasm, had vacuolar nuclei, obvious nucleoli, and easily visible mitotic figures, and were arranged in sheets, islands, or acini, with geoimagedata necrosis. Focal cancer cells were nonadherent and striated. Regarding immunophenotype, SMARCA4 protein (BRG1) was negative in 7/8 and partially positive in 1/8 cases. NGS was performed in 5 cases, of which one had both TP53 and ERBB2 mutations, one had TP53 mutation and NRAS micromutation, one had TP53 mutation alone, one had RET somatic missense mutation, and one had no gene mutation. PD-L1 protein expression was detected in 5 cases, of which one was negative for PD-L1, three had PD-L1 expression, and one had high expression. All patients underwent lobectomy. One case received preoperative adjuvant chemotherapy, and five cases received postoperative adjuvant therapy. Of the total seven patients who were followed from 1 month to 67 months, one had distant metastasis and the other six were alive without recurrence or metastasis.

SMARCA4-dNSCLC is a rare malignant tumor with unique clinicopathological features and special immunohistochemical phenotype, lacks common drug-targeting gene mutations, and has a high positive rate of PD-L1.