Evaluation and therapy of mediastinal thymic cyst.

Two cases of mediastinal thymic cyst are presented. The clinical features of this entity are presented, as well as the case history of the 48-year-old man with an asymptomatic, calcified, cystic anterior mediastinal mass who was followed for four years without significant changes in the mediastinal lesion. Thymic cyst is an identifiable anterior mediastinal mass, in which recurrence following excision or malignant degeneration has never been reported. The risk of mediastinal exploration in a well-demarcated, anterior mediastinal cyst with calcific rim approximates or exceeds the risk of malignancy.