THYMIC HYPERPLASIA IN NEWLY-DIAGNOSED TESTICULAR GERM-CELL TUMORS

Thymic hyperplasia has been reported as a rebound phenomenon in childr en and young people, most commonly following chemotherapy for cancer. Although thymic hyperplasia has been documented in testis cancer patie nts after chemotherapy, to our knowledge it has not previously been re ported in newly diagnosed cases before systemic therapy. A retrospecti ve review of 362 testicular germ cell tumor patients treated at a sing le tertiary care center between January 1, 1980 and August 1, 1993 was performed, with special review of 221 who underwent computerized tomo graphy staging of the chest. Thymic hyperplasia was detected in 4 of t he 221 patients (1.8%) including 3 of 100 (3.0%) with seminoma and 1 o f 121 (0.8%) with nonseminoma. All 4 patients had low stage (I or IIa) disease with a delay in diagnosis (5 to 24 weeks) and thymic hyperpla sia was discovered at staging evaluation 18 to 37 days after orchiecto my but before other cancer therapy was administered. Of the 4 patients 2 underwent thymectomy, revealing histological thymic rebound hyperpl asia. All 4 patients had no evidence of recurrence at 1 to 54 months a fter treatment. In addition to the well known post-chemotherapy phenom enon, thymic hyperplasia may also occur in nonsystemically treated, ne wly diagnosed testicular cancer patients. An anterior mediastinal mass in an otherwise low stage newly diagnosed testicular cancer patient m ay represent thymic hyperplasia and not necessarily metastatic disease .