Morphology of Thymic Remnants Removed after Video-Assisted Thoracoscopic Extended Thymectomy in Patients with Thymomatous Myasthenia Gravis

On a total of 67 patients with Myasthenia Gravis (MG) that had a Video-Assisted Thoracoscopic Extended Thymectomy (VATET) for removal of the thymus gland and cervical and anterior mediastinal fat tissue, 12 revealed a thymoma. Nine patients with capsulated non-invasive thymoma were studied for detection of thymic remnants in cervical and pre-pericardial fat tissue. Six out of nine subjects showed thymic remnants that in half of them demonstrated lymphoid follicular hyperplasia Immunohistochemical characterization of atrophic thymic remnants showed small T-lymphocytes (CD1a; CD3) and rare epithelial cells (EMA; Cytokeratin and LN3). Thymic remnants with lymphoid follicular hyperplasia showed germinal centres positively stained for LN1 (CDw75). Since the last alteration has been considered an important cause of failure of surgical treatment of MG, an accurate investigation and removal of all possible thymic remnants together with the proper thymus may be performed.