Immunological aspects of sarcoidosis associated with true thymic hyperplasia

A 34-year-old woman had a three-month history of a double mitral lesion. Chest radiographs disclosed a mediastinal mass. Thoracotomy was performed and multiple white nodules and an enlarged thymus were seen. Sarcoidosis and true thymic hyperplasia were diagnosed in the excised white nodules and thymus. A decrease of cell-mediated immunity was also discussed. When commissurotomy of the mitral valve was performed 4 months later, sarcoidosis and true hyperplasia had disappeared and alterations of cell-mediated immunity became normal after a course of steroid therapy. The alterations of cell-mediated immunity, so frequent in sarcoidosis, could be related to true thymic hyperplasia.