A 35-year-old Japanese man's routine chest radiography revealed an abnormal opacity. Chest computed tomography and magnetic resonance imaging showed a 5.5 cm in dia. cystic tumor located at the left anterior mediastinum. The tumor was suspected to be an asymptomatic thymic cyst, and we chose observation for the tumor. At the 3-year follow up, the cystic tumor had gradually enlarged to 7.5 cm in...

BACKGROUND To identify and estimate the prevalence of mediastinal cysts lined by the epithelium expressing steroid receptors. METHODS We retrieved 19 mediastinal cysts from our pathology files from 1996 to 2004, and examined estrogen receptor (ER) and progesterone receptor (PR) expressions in the cysts. RESULTS Three paravertebral cysts, all in women, one bronchogenic cyst in a woman, nine ...