A Rare Case of Mixed Type A Thymoma and Micronodular Thymoma with Lymphoid Stroma

• Published in: Journal of pathology and translational medicine Vol. 49; no. 1; pp. 75 - 77
• Main Authors: Cha, Yoon Jin, Han, Joungho, Kim, Jimin, Lee, Kyung Soo, Shim, Young Mog
• Format: Journal Article
• Language: English
• Published: Korea (South) Korean Society of Pathologists, Korean Society for Cytopathology 01.01.2015; The Korean Society of Pathologists and The Korean Society for Cytopathology; Korean Society of Pathologists & the Korean Society for Cytopathology; 대한병리학회
• Subjects: Brief Case Report; Clinical outcomes; Cysts; Histopathology; Lymphoma; 병리학
• ISSN: 2383-7837; 2383-7845
• DOI: 10.4132/jptm.2014.10.27

With its rich B-cells, occasional germinal centers, and nodules of epithelial cells, MNTLS could be misdiagnosed as metastatic carcinoma in a small biopsy specimen.4 Although the histogenesis of MNTLS is not yet clarified, its medullary epithelial cells suggest MNTLS may be a variant of type A thymoma in the setting of thymic B-cell hyperplasia.1 Bcl-2, a B-cell marker, is expressed in type A thymoma and thymic carcinoma.6 We observed Bcl-2 expression in both type A thymoma and MNTLS.Stobel et alJ found that 33% of MNTLS had lymphoid stroma of a monoclonal B-cell population whereas thymic lymphoid hyperplasia or other types of thymoma had a polyclonal population of lymphocytes.Because of the monoclonal lymphoid stroma, they suggested that MNTLS might be a precursor lesion of mediastinal lymphoma.7 In the present case, the lymphoid stroma was positive for both CD20 and CD3, reflecting a polyclonal lymphocyte nature.Corresponding Author Joungho Han, M.D. Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul 135-710, Korea Tel: +82-2-3410-2800, Fax: +82-2-3410-0025, E-mail: hanjho@skku.edu Received: September 2, 2014 Accepted: October 24, 2014 REFERENCES 1.