Benign prostatic hyperplasia in an XX man.

A sixty-nine-year-old white phenotypic male who was being investigated for a myeloproliferative disorder, was found to have an XX karyotype in all cells examined in bone marrow, lymphocytes, and skin fibroblast cultures. Despite essentially no testosterone in the plasma, he also suffered from severe prostatic hyperplasia, a finding not reported previously in patients with this genotype. While endocrine studies showed normal follicle-stimulating hormone, the luteinizing hormone level was twice the upper limit of normal and estrogens were in the normal female range. Except for complete absence of Leydig cells, testicular histology resembled that usually found in Klinefelter syndrome. The patient died of the combined effects of the myeloproliferative disease and urinary tract obstruction. The mechanism of occurrence of the sex chromosome anomaly as well as the cause and implication of the unusual finding of prostatic hyperplasia are discussed.