The study cohort included 47 men with microprolactinoma [age at diagnosis 45.6 ± 17.6 years; median prolactin 70.0 ng/ml (IQR 51.0–103.4); low testosterone, 34 men (72.3%); adenoma diameter 5.6 ± 2.0 mm; median follow-up 7.1 years (IQR 3.5–10.4)]. This evidence concerns the gene PRL and adenoma.