Su Y C, Di J X, Da J P
Department of Pathology, China-Japan Friendship Hospital, Beijing 100029, China.
Zhonghua Bing Li Xue Za Zhi. 2017 May 8;46(5):314-317. doi: 10.3760/cma.j.issn.0529-5807.2017.05.006.
To study the clinicopathologic features, immunophenotype and differential diagnosis of atypical type A thymoma. Clinicopathologic and follow-up data of three cases of atypical type A thymoma from 2004 to 2016 were reviewed. Immunohistochemical staining was performed. All three patients were male with average age of 59 years. Clinically, the lesions presented as anterior mediastinal masses. Grossly, the tumor ranged in size from 4 to 6 cm in greatest dimension and partially enclosed within fibrous capsule. The cut surface was homogenously fleshy, tan to brown in color, with multinodular and lobulated configurations. Cystic changes and necrosis were seen. Microscopically, the tumor was composed of plump spindle or oval-shaped cells arranged in storiform, microcystic, glandular, rosettes-like and hemangiopericytoma-like histological patterns. The tumor cells showed mild cytological atypia and mitotic activity ranged from 4 to 5/10HPF. Necrosis was present in all tumors. All tumors showed diffuse CK(AE1/AE3), CK19, p63 and vimentin expression. TdT, CK20, CD20, CD5 and CD117 were negative. The proliferative index, as measured with Ki-67, was 15.2% to 26.4%. None of the cases had recurrence or metastases during the follow-up period (9 to 27 months). Atypical type A thymoma presents atypical features including tumor necrosis and increased mitotic activity. However, the implications of such atypical features to the biological behavior of the tumor remain to be determined.
研究非典型A型胸腺瘤的临床病理特征、免疫表型及鉴别诊断。回顾2004年至2016年3例非典型A型胸腺瘤的临床病理及随访资料。进行免疫组织化学染色。3例患者均为男性，平均年龄59岁。临床上，病变表现为前纵隔肿块。大体上，肿瘤最大径为4至6 cm，部分被纤维包膜包裹。切面质地均匀呈肉质，颜色为棕褐色至褐色，呈多结节状和分叶状。可见囊性变和坏死。显微镜下，肿瘤由丰满的梭形或椭圆形细胞组成，排列成漩涡状、微囊状、腺管状、玫瑰花结样和血管外皮细胞瘤样组织学模式。肿瘤细胞显示轻度细胞学异型性，有丝分裂活性为4至5/10HPF。所有肿瘤均有坏死。所有肿瘤均显示弥漫性细胞角蛋白(AE1/AE3)、细胞角蛋白19、p63和波形蛋白表达。末端脱氧核苷酸转移酶、细胞角蛋白20、CD20、CD5和CD117均为阴性。用Ki-67测量的增殖指数为15.2%至26.4%。随访期间(9至27个月)，所有病例均无复发或转移。非典型A型胸腺瘤具有包括肿瘤坏死和有丝分裂活性增加在内的非典型特征。然而，这些非典型特征对肿瘤生物学行为的影响仍有待确定。
