Clinicopathological observation of micronodular thymic epithelial tumors with lymphoid stroma

doi:10.3969/j.issn.1006-7795.2018.03.022

Abstract

Abstract: Objective To investigate the clinicopathological features and prognosis of micronodular thymic epithelial tumors with lymphoid stroma.Methods Four cases of thymic epithelial tumours characterized by micronodular proliferation of tumour cells separated by abundant lymphoid stroma were collected in China-Japan Friendship Hospital from January 2014 to January 2018. Hematoxylin-Eosin staining, immunohistochemistry and in situ hybridization were performed to evaluate the pathological features.Results The average age of the 4 patients was (66.5±10.4) years, including 1 male and 3 female. All the patients had an anterior mediastinal mass without myasthenia gravis or autoimmune disease. The tumors were characterized by micronodular proliferation of tumour cells separated by abundant lymphoid stroma with prominent germinal centers. Two of them showed cytological atypia and increased nuclear mitosis. Immunohistochemical study showed that the tumor cells were strongly positive for CK and CK5/6. Additionally, the tumor cells with atypia were positive for CD5, CD117 and Bcl-2. Scattered CD3, CD5 and TdT positive immature T lymphocytes were noted in and around tumor nodules in 3 cases. EB virus was not detected in both tumor cells and lymphocytes. Altogether, 2 cases were diagnosed as micronodular thymoma with lymphoid stroma (MNT), 1 atypical variant of MNT, and 1 micronodular thymic carcinoma with lymphoid stroma. There was no tumor recurrence in 4 to 42 months after the operation.Conclusion Micronodular thymic epithelial tumor with lymphoid stroma is a kind of rare thymus tumor, and may constitute a spectrum in the continuum of benign and malignant lesions. Their prognosis is good after complete resection. The diagnosis should be based on a combination of clinicopathologic features and other types of thymus tumor should be excluded. The treatment should be conservative.

Key words: thymoma, thymic carcinoma, micronodular, lymphoid stroma, diagnosis

CLC Number:

R736.3

Wang Bei, Liu Hongyan, Zhang Honglei, Wang Xiuhong, Da Jiping. Clinicopathological observation of micronodular thymic epithelial tumors with lymphoid stroma[J]. Journal of Capital Medical University, 2018, 39(3): 433-438.

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URL: https://journal03.magtech.org.cn/Jweb_sdykdxxb/EN/10.3969/j.issn.1006-7795.2018.03.022

https://journal03.magtech.org.cn/Jweb_sdykdxxb/EN/Y2018/V39/I3/433

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