Abstract
Thymic cyst is a relatively rare mediastinal tumor. Six cases of thymic cyst were treated in our institution and the intracystic fluids were studied. The 6 cases accounted for 5.2% of all mediastinal tumors and 35% of congenital cysts. Five of the 6 patients had no symptoms and one had chest oppression. There were no associated diseases such as myasthenia gravis. CT scan showed a homogeneous water density area which was demonstrated as a low intensity area on Tl-weighted and high intensity on T2-weighted MR images. Thallium scintigram showed a defect at the site of the lesion. All the 6 cases underwent surgical resection without cyst recurrence. All surgical specimens were histologically diagnosed as thymic cysts. Analysis of the intracystic fluid revealed a high titer of CAl25, a low titer of total protein and LDH, and uniform titer of sodium. These results indicated that percutaneous aspiration might be useful for diagnosis and therapy of a thymic cyst if it has no sign of malignancy.
