Hypopituitarism patterns and prevalence among men with macroprolactinomas.

PURPOSE: Men with prolactin-secreting tumors usually harbor macroadenomas. The degree of pituitary dysfunction may vary among different adenoma size subgroups, as is recovery after treatment. Our study purpose was to characterize hypopituitarism and recovery after treatment in men with macroprolactinomas.
METHODS: A retrospective study, including a consecutive group of 81 men with pituitary macroadenomas (≥10 mm) and hyperprolactinemia (>7×ULN). Patients were divided into three categories according to adenoma size at presentation: 10-19 mm (group A), 20-39 mm (group B), and ≥40 mm (group C). We compared total testosterone, gonadotropins, cortisol, thyroid hormones and hemoglobin levels at presentation and after treatment.
RESULTS: Eighty-one patients were included; 24, 31 and 26 patients in groups A, B and C, respectively. Pretreatment hypogonadism prevalence was 75.0, 93.5 and 90.9% (p = 0.046; A vs B and C), central hypocortisolism - 0, 6.9 and 33.3% (p = 0.005), and central hypothyroidism - 6.7, 17.9 and 26.1% (NS) in groups A, B and C, respectively. Only 26.7% of all patients presented with hypocortisolism and/or hypothyroidism (42.9% in group C). Anemia (Hb < 13.5 g%) was detected in 31.3, 57.1 and 80.0% in groups A, B and C, respectively (p = 0.04). Larger adenoma diameter correlated strongly with lower FT4 levels following treatment (r = -0.42, p = 0.043).
CONCLUSIONS: Macroprolactinomas in men caused partial hypopituitarism, affecting testosterone in all adenoma size groups and cortisol more in patients with larger adenomas. However, most of the men did not have pituitary hormones affected, beside testosterone. Most patients recovered central hypocortisolism but not hypothyroidism following treatment.