Clinical and occult testicular leukemia in long-term survivors of acute lymphoblastic leukemia.

Twenty-nine of 60 boys with acute lymphoblastic leukemia survived for more than 30 months and were potential candidates for discontinuation of therapy. Six patients developed overt clinical testicular leukemia: one at 34 months from diagnosis while receiving therapy and five at three to 17 months after therapy was stopped. Elective wedge biopsy of the testes has become part of the evaluation prior to discontinuation of therapy since 1977. Six of 18 boys had microscopic evidence of leukemic infiltration of the testes: four with diffuse involvement and two with focal clusters of leukemic cells. Testicular biopsy is recommended at the time of discontinuation of therapy and perhaps early in the course of the disease, although a negative biopsy does not exclude some focal lesions. The eventual outcome of those with occult testicular leukemia remains to be determined.