Thymic hyperplasia following chemotherapy of a testicular germ cell tumor. Immunohistological evidence for a simple rebound phenomenon.

Diffuse thymic hyperplasia after chemotherapy of a mixed testicular germ cell tumor is reported in a 16-year-old patient. The immunohistologic investigation of the enlarged thymus revealed a normal distribution and antigen expression of lymphocytes and epithelial cells. There was no evidence of selective proliferation of lymphocytic or nonlymphocytic subpopulations within the thymus. Thus, our data corroborate the identification of thymic enlargement after chemotherapy as a simple rebound phenomenon.