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Vol.40 No.7 contents | Japanese/English |
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- Case Report -
A Case of Giant Atypical Thymoma in the Thoracic Cavity
Mamoru Koga, Kazumitsu Ohmori, Masae Hasegawa and Nanao NegishiSecond Department of Surgery, Nihon University School of Medicine
Case: A 47-year-old company employee had no remarkable past history and physical examination performed in November 1997 yielded no abnormal findings, but chest radiography performed in November 1998 revealed an abnormal shadow. The tumor was 15×10 cm and in the left thoracic cavity involved the pulmonary vein, lingular segment and the chest wall. Needle biopsy yielded a diagnosis of thymoma. The patient received 2 courses of chemotherapy (ADOC) but the tumor size only reduced 11%, which was changed as no change. Thereafter, extended thymectomy was performed with combined resection of the pericardium, the left upper lobe of the lung, and S6, through a median sternotomy and additional postero-lateral thoracotomy. The resected specimen was Masaoka's stage III, invading the pericardium and the left upper lobe of the lung. The margin was negative, indicating a successful radical resection. Immunohistochemical investigation showed dense staining with bcl-2 and Ki67 (MIB-1), suggesting increased proliferative activity. Staining with O13 (MIC2) showed that the lymphocytes infiltrating the tumor were immature. Therefore, the tumor was not thymic carcinoma, but was atypical thymoma. Conclusion: Analysis of lymphocyte surface markers was useful in making differential diagnosis between invasive thymoma and thymic carcinoma.
key words: Atypical thymoma, Thymic carcinoma, T-lymphocyte, MIC2 antibody
Received: July 14, 2000
Accepted: August 25, 2000
JJLC 40 (7): 759-763, 2000
