Thymic hyperplasia. II. Lymphofollicular hyperplasia of the thymus. An immunohistologic study

The so-called lymphofollicular hyperplasia, which is caused by the occurrence of hyperplastic lymph follicles within the organ, is constantly associated with autoimmune diseases (e.g., myasthenia gravis) and in rare instances with malignant tumors. The architecture of lymphofollicular hyperplasia was studied immunohistochemically using antibodies against epithelial, vascular, lymphocytic, and histiocytic antigens. There is evidence, that the configuration, microtopography, cellular composition, and immunohistological findings of the lymph follicles with germinal centers in the myasthenic thymus are essentially the same as in those occurring in lymph nodes and in other lymphatic tissue. Furthermore it could be shown that the follicles originate in the interlobular septal space and displace the thymic parenchyma by extension.