Immunophenotyping to detect and characterize acute lymphocytic leukemia in testicular biopsies

This study establishes the utility of immunophenotyping testicular biopsy specimens in patients with acute lymphoid leukemia. The value of immunophenotyping in detecting or excluding leukemic testicular infiltration is demonstrated in six children with acute lymphocytic leukemia. A panel of monoclonal antibodies was employed on snap-frozen testicular biopsies, allowing both detection and immunologic characterization of four neoplastic lymphocytic infiltrates. Two samples were proven both histologically and phenotypically negative for leukemic infiltration. One of the four leukemic cases was clinically silent and might have escaped detection except for phenotyping. One leukemic infiltrate was also suspected to possess a multidrug-resistant phenotype (p-glycoprotein +); the latter possibility was excluded by an absence of reactivity with anti-p-glycoprotein monoclonal antibody. Thus, three clinically useful applications are demonstrated: (1) confirmation of testicular leukemic relapse, gaining assertion in histologically uncertain cases; (2) exclusion of clinically suspected disease relevant to cessation of therapy, and (3) detection/exclusion of drug-resistant phenotypes. Unexpectedly, we found expression of plasma cell-associated antigen in testicular germ cells, which may prove to be diagnostically useful in the future evaluation of germ cell tumors.