Endocrine Abstracts

Introduction: Non-functioning pituitary adenomas (NFPA) accounts for about 40% of all pituitary tumors. One or more anteropituitary deficiencies are present at diagnosis in 60–80% of NFPA. Hypopituitarism classically appears with the following order: GH→FSH/LH→TSH→ACTH. Aim of the study was to evaluate the incidence and the order of appearance of pituitary deficiencies in patients with NFPA.

Materials and methods: We retrospectively analyzed the data of 260 NFPA (56% females) followed at our center from 1990 to 2013. At diagnosis all patients underwent a complete evaluation of basal anteropituitary function. Provocative tests for hypotalamic–pituitary–adrenal axis were performed in 234/260. ACTH deficiency was defined by either basal serum cortisol <5 μg/dl, peak of cortisol following ACTH 250 μg stimulation test or insulin tolerance test <18 μg/dl.

Results: At diagnosis, the average age was 50.4±17 years. 63% of patients had a macroadenoma. 50.8% of patients (63% macroadenomas and 29.5% microadenomas) presented at least one anteropituitary deficiency with the following prevalence: 31.6% hypogonadism, 26.7% GH deficiency, 23.9% hypoadrenalism and 13.9% hypothyroidism. In particular, 30% of patients had an isolated deficiency (28% in micro and 30% in macro) and 22% multiple deficiencies (3% in micro and 35% in macro). Isolated deficiencies were represented by hypogonadism in 11.3% of patients (6.7% micro and 14.4% macro), hypoadrenalism in 9.5% (12.3% in micro and 7.6% in macro) and GH deficiency in 8.6% (9.1% in micro and 8.3% in macro).

Conclusions: One-third of patients with a microadenoma had at least one anterior pituitary hormonal deficiency at diagnosis. The presence of patients with isolated hypoadrenalism and hypogonadism suggests that the order of appearance of hypopituitarism does not always follow the one expected. In particular, given the relative high prevalence of isolated hypoadrenalism even in microadenomas, we suggest the full assessment of basal and dynamic anterior pituitary function in all patients with NFPA regardless of tumor size.