Sonobe Hiroshi, Omote Rika, Habara Toshiyuki, Washio Kazuhiro, Yamazoe Nobuyoshi, Matsumoto Shinji, Nabeshima Kazuki, Toda Hiroko
Department of Diagnostic Pathology, National Hospital Organization Fukuyama Medical Center, Fukuyama, JPN.
Department of Clinical Laboratory, Chugoku Central Hospital of the Mutual Aid Associations of Public School Teachers, Fukuyama, JPN.
Cureus. 2024 Jun 12;16(6):e62212. doi: 10.7759/cureus.62212. eCollection 2024 Jun.
Herein, we report a rare case of pleural epithelioid malignant mesothelioma with a prominent myxoid stroma. To date, detailed morphological or molecular pathological findings have not been reported for this type of tumor. Hence, we aimed to describe the cytological, histological, immuno-cytohistological, electron-microscopic, and molecular pathological findings using fluorescence in situ hybridization (FISH) in such a case. The patient was a male in his mid-sixties with a history of asbestos exposure and had originally visited the hospital with a persistent cough and fever. Chest radiography revealed left pleural effusion, and laboratory examination revealed a high titer for hyaluronic acid in the effusion. Additionally, computed tomography revealed diffuse multinodular or cystic lesions in the left parietal pleura, and pleural effusion cytology revealed large epithelioid cells with mild nuclear atypia, which were considered reactive mesothelial cells. Cytologically, Giemsa staining revealed that these cells harbored variously sized intracytoplasmic vacuoles that were Alcian-blue-positive, suggesting hyaluronan production. Biopsy revealed large epithelioid cells that loosely proliferated against a prominent myxoid background. These cells were immuno-positive for calretinin, Wilms' tumor 1, D2-40, vimentin, and cytokeratin AE1/AE3 but not for carcinoembryonic antigen, Ber-EP4, or desmin. BRCA 1 associated protein 1 immunostaining showed nuclear loss, and FISH showed homozygous deletion of cyclin-dependent kinase inhibitor 2A (p16) on chromosome 9p21. Based on these findings, the lesion was diagnosed as an epithelioid mesothelioma with a prominent myxoid stroma. Electron-microscopy demonstrated a dense microvillus pattern on the surface of the tumor cells, indicating a mesothelial cell origin, and variously sized vacuoles in the cytoplasm, confirming the presence of intracytoplasmic vacuoles demonstrated on cytology. The tumor tissues obtained during surgery harbored prominent myxoid stroma, which proved that the present tumor was consistent with this type of mesothelioma. After informed consent was obtained, the patient and family wished for total resection of the tumor and postoperative chemotherapy, and the patient eventually died eight months after surgery.
在此，我们报告一例罕见的伴有显著黏液样基质的胸膜上皮样恶性间皮瘤病例。迄今为止，尚未有关于此类肿瘤详细的形态学或分子病理学发现的报道。因此，我们旨在描述该病例中使用荧光原位杂交（FISH）技术的细胞学、组织学、免疫细胞组织学、电子显微镜及分子病理学发现。患者为一名65岁左右男性，有石棉接触史，最初因持续咳嗽和发热就诊。胸部X线检查显示左侧胸腔积液，实验室检查显示胸腔积液中透明质酸滴度较高。此外，计算机断层扫描显示左侧壁层胸膜有弥漫性多结节或囊性病变，胸腔积液细胞学检查发现大的上皮样细胞，核异型性轻微，考虑为反应性间皮细胞。细胞学上，吉姆萨染色显示这些细胞含有大小不一的胞质内空泡，阿尔辛蓝染色呈阳性，提示有透明质酸产生。活检显示大的上皮样细胞在显著的黏液样背景中松散增殖。这些细胞钙视网膜蛋白、肾母细胞瘤1、D2 - 40、波形蛋白和细胞角蛋白AE1/AE3免疫阳性，但癌胚抗原、Ber - EP4或结蛋白免疫阴性。BRCA 1相关蛋白1免疫染色显示细胞核缺失，FISH显示9号染色体p21上细胞周期蛋白依赖性激酶抑制剂2A（p16）纯合缺失。基于这些发现，该病变被诊断为伴有显著黏液样基质的上皮样间皮瘤。电子显微镜显示肿瘤细胞表面有密集的微绒毛模式，表明为间皮细胞起源，细胞质中有大小不一的空泡，证实了细胞学上所见的胞质内空泡的存在。手术中获取的肿瘤组织有显著的黏液样基质，证明目前的肿瘤符合此类间皮瘤。在获得知情同意后，患者及其家属希望进行肿瘤全切及术后化疗，患者最终在手术后8个月死亡。
