Correlation of gonadal function with histology of testicular biopsies at treatment discontinuation in childhood acute leukemia.

Testicular open-wedge biopsy was performed in 35 children in complete remission from acute lymphoblastic leukemia without clinical signs of leukemic testicular infiltration at the time of treatment discontinuation. Histological investigation showed thickening of the tunica propria of the seminiferous tubules in 13 of 35 patients. In 5 of 35 patients, the tubular fertility index was markedly reduced; in 5 of 6 pubertal patients, decreased spermatogenesis or aplasia of germinal epithelium was observed. Histologic damage was found mainly in the germinal cells both in patients treated with cytosine arabinoside and cyclophosphamide and in those treated with antiblastic drugs not considered damaging to the gonads. The extent of impairment was independent of age at start of treatment. On the other hand, endocrinological investigation carried out at the crucial moment of treatment suspension showed normal hypothalamic-hypophyseal-gonadal function as well as normal anthropometric data, bone age, and pubertal stage in the majority of patients. Testicular leukemia was found in only one patient (2.8%) whereas three children with negative testicular biopsies had testicular relapses within 7 months. Therefore, in view of the limits of light microscopy in diagnosing leukemic infiltration at treatment discontinuation, we propose the use of more sophisticated techniques, possibly within 6 months of suspension of therapy.