Objective: To investigate the clinical, cytomorphology, immunocytochemical and molecular features of metastatic melanoma in serosal cavity effusion. Methods: Cytological specimens of 14 patients with melanoma in the chest and abdomen were collected from 2017 to 2023, at the Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. SOX10, S-100 protein, PRAME, BRAF V600E, HMB45, and Melan A were detected by immunocytochemical methods. Fourteen cases were tested for routine antibody combinations, including Claudin4, HEG1, Calretinin, CD68, etc. Four of the patients had biopsy or surgical samples of metastatic solid lesions of primary sites, and further next-generation sequencing (NGS) or amplification refractory mutation system (ARMS)-PCR molecular test was performed. In addition, 30 cases of serosal effusion samples were collected as control groups (10 cases of benign mesothelial cell reactive hyperplasia, 10 cases of mesothelioma, and 10 cases of metastatic lung adenocarcinoma). Results: Among the 14 cases of melanoma, there were 7 males and 7 females, with ages ranging from 35 to 86 years, and an average age of 57 years, there 10 cases aged ≥50 years. The tumor cells in the serosal effusion varied in morphology and degree of atypia. SOX10 was positive in all 14 cases (14/14), S-100 protein was positive in 10 cases (10/14), PRAME was positive in 12 cases (12/14), BRAF V600E was positive in 10 cases (10/14), HMB45 was positive in 12 cases (12/14), and Melan A was positive in 13 cases (13/14). In 4 patients with histological correlation, the cytological and histological expression of SOX10, BRAF V600E, and PRAME was positive in all 4 cases (4/4); S-100 protein was positive in 2 cases (2/4); and HMB45 and Melan A were positive in 3 cases (3/4). Using NGS or ARMS-PCR, missense mutations of BRAF V600E were detected in all 4 patients; TERT promoter mutations was detected in 1 case; and CDKN2A terminating mutations and MSI1 deletion mutations were detected in the other case. SOX10, S-100, HMB45, Melan A, PRAME and BRAF V600E were all negative in 30 control samples of serosal cavity effusion. Conclusion: By observing the morphology of tumor cells, immunocytochemical test of several combination markers, especially the expression of SOX10, BRAF V600E and PRAME, can help to improve the positive diagnosis rate of melanoma in serous cavity effusion.
目的: 探讨浆膜腔积液转移性黑色素瘤的临床表现、细胞学形态、免疫细胞化学及分子病理特征。 方法: 收集华中科技大学同济医学院附属协和医院2017—2023年14例发生于胸腔及腹腔转移性黑色素瘤的细胞学标本,应用免疫细胞化学染色方法检测SOX10、S-100蛋白、PRAME、BRAF V600E、HMB45、Melan A;同时14例均检测了常规用于鉴别诊断的抗体组合,包括Claudin4、HEG1、Calretinin、CD68等。其中4例患者有转移性实体病灶或原发灶的活检或手术标本对照,并进一步行二代测序或扩增阻滞突变系统(ARMS)-PCR分子检测。另收集30例浆膜腔积液标本作为对照组(10例良性浆膜腔积液病例、10例间皮瘤、10例转移性肺腺癌)。 结果: 14例黑色素瘤患者中,男性7例,女性7例,年龄35~86岁(平均年龄57岁,≥50岁患者10例)。浆膜腔积液中黑色素瘤细胞形态多样,异型性程度不等。所有14例均弥漫表达SOX10(14/14),S-100蛋白阳性比例为10/14,PRAME阳性比例为12/14,BRAF V600E阳性比例为10/14,HMB45阳性比例为12/14,Melan A阳性比例为13/14。4例有组织学对照的患者,SOX10、BRAF V600E、PRAME免疫组织化学结果与细胞学结果一致(4/4),S-100蛋白细胞学与组织学的表达一致比例为2/4,HMB45、Melan A细胞学与组织学的表达一致比例为3/4。二代测序及ARMS-PCR检测均检出BRAF V600E的错义突变(4/4),其中1例还检出TERT启动子突变,另1例检出CDKN2A终止突变及MSI1的缺失突变。30例浆膜腔积液对照标本均不表达SOX10、S-100蛋白、HMB45、Melan A、PRAME、BRAF V600E。 结论: 通过观察肿瘤细胞的形态,免疫细胞化学检测几种组合标志物,尤其是SOX10、BRAF V600E及PRAME的表达情况,有助于提高浆膜腔积液中黑色素瘤的阳性诊断率,为临床后续治疗方案的选择提供参考依据。.