Terada Tadashi
Department of Pathology, Shizuoka City Shimizu Hospital, Miyakami 1231, Shimizu-Ku, Shizuoka, 424-8636, Japan.
Med Oncol. 2009;26(2):247-50. doi: 10.1007/s12032-008-9116-5. Epub 2008 Nov 7.
The author reports herein an extremely rare case of primary small cell carcinoma of the mediastinum with an emphasis on KIT and PDGFRA genes. A 66-year-old man was found to have a mediastinal tumor on a routine chest X-ray examination, and was admitted to our hospital. Imaging modalities revealed a 5 x 4 cm tumor in the middle mediastinum near the bronchial carina. No other tumors were detected in the body including the lungs. Video-assisted thoracoscopy confirmed the mediastinal tumor, and a large incisional biopsy was performed. The tumor was histologically small cell carcinoma. An immunohistochemical study revealed positive reactions for cytokeratins (AE1/3, polyclonal), synaptophysin, neuron-specific enolase, CD56, KIT, and PDGFRA, and negative reactions for chromogranin, CEA, CD45, CD20, and CD3. Ki-67 labeling showed a value of 80%. A molecular genetic analysis using PCR-direct sequencing identified no mutations of KIT (exons 9, 11, 13, and 17) and PDGFRA (exons 12 and 18) genes. The patient received radiation and chemotherapy, and the tumor was fully resolved. The patient has remained free of recurrence for 6 years after the first presentation. The present case is the first reported case of primary small cell carcinoma of the mediastinum with an examination of KIT and PDGFRA expressions and KIT and PDFGRA gene mutations.
作者在此报告一例极其罕见的纵隔原发性小细胞癌病例，重点关注KIT和PDGFRA基因。一名66岁男性在常规胸部X线检查中发现纵隔肿瘤，随后入住我院。影像学检查显示在支气管隆突附近的中纵隔有一个5×4 cm的肿瘤。身体其他部位包括肺部未检测到其他肿瘤。电视辅助胸腔镜检查证实了纵隔肿瘤，并进行了大块切开活检。肿瘤组织学检查为小细胞癌。免疫组织化学研究显示细胞角蛋白（AE1/3，多克隆）、突触素、神经元特异性烯醇化酶、CD56、KIT和PDGFRA呈阳性反应，嗜铬粒蛋白、癌胚抗原、CD45、CD20和CD3呈阴性反应。Ki-67标记显示值为80%。使用PCR直接测序的分子遗传学分析未发现KIT（外显子9、11、13和17）和PDGFRA（外显子12和18）基因的突变。患者接受了放疗和化疗，肿瘤完全消退。自首次就诊后，患者已无复发存活6年。本病例是首例报道的对KIT和PDGFRA表达及KIT和PDFGRA基因突变进行检测的纵隔原发性小细胞癌病例。
