Last update:
05-Dec-2009

OBJECTIVE The effects of thymectomy were studied in patients with thymoma.

METHOD Investigation was made in 41 patients who underwent thymectomy, with particular emphasis on 26 cases of myasthenia gravis (MG), in comparison with 4 cases of thymic carcinoma.

RESULTS Lymphocyte predominant thymoma was the most frequent histological type (44%). One patient with MG both and a thymoma composed of lymphocytes mixed with epithelial cells presented ectopic thymoma in the pleura and lung 6, 11 and 12 years after thymectomy, which displayed increased atypia, resembling that seen in a case of intra-tracheal thymic carcinoma. Among the 26 patients with MG, 23 (88%) were positive for anti-acetylcholine receptor (AChR) antibody (Ab). Fifteen (65%) MG cases had peak values of AChR Ab before thymectomy. One patient with MG had anti-cardiolipin-β2 glycoprotein 1 (CL-β2GP1) Ab. Prolonged aPTT of 428-200.0 sec was observed in MG patients. Complications among the 26 patients with MG were hepatic vein thrombosis (HVT) in 6, portal vein thrombosis in 1 and ileus in 2 cases, occurring 5 days to 6 years after thymectomy. In addition, myocardial infarction, deep vein thrombosis after cerebral infarction and pulmonary embolism were each observed in 1 patient with MG.

CONCLUSIONS Post-thymectomy HVT and ileus did not result in severe infarction. Autoimmunity was improved due to a decrease in AChR Ab observed 1 month post-thymectomy. Pleural and lung ectopic thymoma with gradually elevating atypia in one benign thymic thymoma were judged to be caused by aberrations rather than by metastases.

Key words: Anti-acetylcholine receptor antibody, Autoimmunity, Ectopic thymoma, Hepatic vein thrombosis, Ileus, Myasthenia gravis, Portal vein thrombosis, Thymectomy, Thymic carcinoma, Thymoma.