[The structure of the germinal centers of the thymus]

A morphological investigation of the thymus was performed in 82 patients dead from rheumatism. The germinal centers of the thymus localized in the cortical layer and medullary substance were found in 42% of observations. These centers were not homogeneous in their structure. Some of them represent germinal centers of lymphoid nodules, others have epithelioreticulocytes. The latters having a substantial difference from the centers of the lymphoid nodules should be referred to as thymic islands. Necrosis of their cells appear in these islands, its spreading being responsible for transformation of the islands in cysts. The appearance of islands and the following necrosis are thought to be a mechanism of elimination of the thymus cells.