Sequential testicular biopsies in childhood acute lymphocytic leukemia.

Between August 1978 and November 1981, 33 boys with acute lymphocytic leukemia (ALL) (26 non-T, 7 T-cell) younger than 16 years underwent bilateral wedge testicular biopsies at the time of initial diagnosis. Seven (4 non-T, 3 T-cell) demonstrated focal leukemic infiltrates. Rebiopsy after successful induction therapy without testicular irradiation showed eradication of leukemic infiltrates in five, persistent focal infiltrates in one, and a diffuse infiltrate in one. The two patients who had persistent leukemic involvement had a T-cell phenotype, and in one of them overt testicular disease developed 2 years later. All 33 patients were followed prospectively for a minimum of 3 years. Fifteen (14 non-T, 1 T-cell) remained in remission for 3 years and underwent another testicular biopsy before the cessation of therapy. Two patients, both non-T and both of whom were free of testicular involvement at diagnosis, showed testicular infiltrates at that time. Of the seven boys with positive specimens at diagnosis, only two remained disease-free for 3 years and showed no testicular involvement upon the completion of chemotherapy. In this study, microscopic testicular involvement by lymphoblasts occurred in 21% of newly diagnosed boys with ALL; this occurred only if the leukocyte count exceeded 25,000/microliter. These patients in general had a poor prognosis, probably reflecting the overall heavy tumor burden. However, it was not possible to predict accurately those patients who would have leukemic testicular infiltrates at the cessation of chemotherapy by performing biopsy of the testes at the time of initial diagnosis or after induction therapy.