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Vol.38 No.7 contents | Japanese/English |
- Case Report -
Thymic Carcinoma Misclassified as Thymoma by Fine Needle Aspiration Biopsy: Usefulness of Immunohistochemical Staining of Needle Biopsy Specimens
Yushi Saito, Yosuke Yamakawa, Masanobu Kiriyama, Ichiro Fukai, Satoshi Kondo, Yoshitaka Fujii, Hisashi Tateyama* and Tadaaki Eimoto*The Second Department of Surgery, The Second Department of Pathology*, Nagoya City University Medical School
We present two surgically treated cases of thymic carcinoma which were misclassified as atypical thymoma by preoperative needle biopsy which showed epithelial tumors with mild cytological atypia and lymphocytic infiltration. Immunohistochemical staining for bcl-2 and MIB-1 was performed on paraffin-embedded sections from these two thymic carcinomas and four thymomas underwent mediastinal needle biopsy. Strong immunoreactivity for bcl-2 expression of thymic carcinomas and little staining of thymomas were seen. MIB-1 labeling indices of thymic carcinomas (14.0%, 14.6%) were higher than those of thymomas (1.0%∼3.6%). In some cases, it may be difficult to distinguish thymic carcinoma from thymoma by small needle biopsy specimens, and immunostaining reactivity of bcl-2 and MIB-1 may be a useful adjunct to differentiate thymic carcinoma from thymoma even in needle biopsy specimens.
key words: Thymoma, Thymic carcinoma, Needle biopsy, bcl-2, MIB-1
Received: April 30, 1998
Accepted: November 5, 1998
JJLC 38 (7): 863-870, 1998
