Endocrine Abstracts

Aims: To evaluate the clinical features and long-term therapeutic outcome of giant prolactinoma (gPRLoma) in men and to compare them with those of a group of male patients with non-gPRL macroprolactinomas (non-gPRLomas).

Patients and methods: A retrospective and multicenter study of gPRLomas in men diagnosed in a 20-year period was performed. Clinical data and treatment outcome were registered. The diagnosis of gPRLoma was established when the maximal tumor diameter was ≥ 40 mm or the tumor had ≥20 mm of suprasellar extension associated to hyperprolactinemia (PRL>1000 ng/ml). Non-gPRLoma was considered when tumor diameter was ≥ 10 mm and <40 mm associated to hyperprolactinemia (PRL ≥ 200 ng/ml).

Results: Twenty three patients with gPRLoma (age 38.3±13.5 yr) followed for at least 3 mo were evaluated. A group of 42 patients with non-gPRLoma served as a control group. More than half (56.5%) of the gPRLoma patients were younger than 40 years at diagnosis. Visual disturbances were significantly more common in gPRLoma than in non-gPRLoma patients (65.2 vs 25.6%; P=0.004). Prevalence of hypopituitarism was similar in both groups of patients (73.9% vs 80.9%; gPRLoma vs non-gPRLoma; NS). Serum PRL concentrations were significantly higher in gPRLoma than in non-gPRLoma patients [median (IR), 3978 ng/ml (1179-9012) vs 907 ng/ml (428-3119); P<0.001]. Maximum tumor diameter in gPRLomas was 4.8±0.8 cm and 2.4±0.7 cm in non-gPRLoma (P<0.001). All patients were treated with dopamine agonists (DA). Surgery was used in 12 (52.2%) gPRLoma patients and in 12 (28.6%) non-gPRLoma patients (P=0.054). Lastly, radiotherapy was used in 5 (21.7%) gPRLoma patients and in 6 (14.2%) non-gPRLoma patients (NS). At last visit, PRL was similar in both groups of patients and tumor size decreased significantly (P<0.001) in both groups of patients. Clinical cure (maintained normoprolactinemia without therapy for > 1 yr and no radiological evidence of pituitary tumor) was achieved in 2 (8.7%) gPRLoma patients and in 2 (4.8%) non-gPRLoma patients (NS).

Conclusion: gPRLomas in men are usually diagnosed at the age of 40 yr, an age similar to that of non-gPRLomas. The only clinical difference with non-gPRLomas is their greater prevalence of visual disturbances. The therapeutic approaches and tumor outcomes were similar to those obtained in patients with non-gPRLomas. Complete cure in gPRLoma is rare, but similar to that achieved in non-gPRLomas, reaching in less than 10% of patients.