Prevalence of hypothalamic-pituitary imaging abnormalities in impotent men with secondary hypogonadism

Purpose: Because prevalence of structural lesions of the pituitary and hypothalamus in impotent men with secondary hypogonadism was undefined, we evaluated 164 men 27 to 79 years old whose chief complaint was erectile dysfunction and who repeatedly had low serum testosterone levels (less than 230 ng./dl.). Materials and Methods: With computerized tomography or magnetic resonance imaging of the sella we detected potentially serious lesions (pituitary lesions greater than 5 mm. or any hypothalamic lesion) in 11 men (6.7%, 95% confidence interval 2.9 to 10.5%), including 5 pituitary microadenomas (5 mm. or larger), 4 pituitary macroadenomas and 2 hypothalamic lesions. Results: Mean serum testosterone was lower in patients with (121 +/-: 66 ng./dl., standard deviation) than without (177 +/- 39 ng./dl.) hypothalamic or pituitary imaging abnormalities (p <0.001). For every 10 ng./dl. decrease in testosterone the risk of hypothalamic or pituitary imaging abnormalities increased 1.2-fold (p <0.005). Macroadenomas and hypothalamic lesions were confined to 6 subjects with testosterone levels of 104 ng./dl. or less. Conclusions: The risk of hypothalamic or pituitary imaging abnormalities is low among men evaluated for erectile dysfunction and secondary hypogonadism. However, this risk increases markedly when the serum testosterone level is markedly decreased.