Hypothalamic-Pituitary Axis in Non-Functioning Pituitary Adenomas: Focus on the Prevalence of Isolated Central Hypoadrenalism.
BACKGROUND
Non-functioning pituitary adenomas (NFPA) account for about 40% of pituitary tumors. Pituitary deficiencies are present at diagnosis in 60-80% of NFPA, and, classically, growth hormone (GH) secretion is lost first, while adrenocorticotropic hormone is expected to disappear last. The aim of this study was to evaluate the incidence of multiple or isolated pituitary deficiencies in a large series of NFPA.


METHODS
We retrospectively analyzed data on 218 NFPA cases (59% females, 59% with macroadenomas, average age: 50.2 ± 17 years) followed up at our center from 1990 to 2013. At diagnosis all patients had a complete evaluation of pituitary function in basal conditions and provocative tests for the hypothalamic-pituitary-adrenal axis, while tests for GH deficiency (GHD) were carried out in 38%.


RESULTS
52.3% of patients (65.6% of macroadenomas, 33.3% of microadenomas) presented at least 1 pituitary deficiency: isolated deficiency in 29.8%, multiple deficiencies in 30% and panhypopituitarism in 9%. Isolated deficiencies were hypogonadism in 11.5% of patients (8% in micro-, 14% in macroadenomas), hypoadrenalism in 10.1% (14% in micro-, 7% in macroadenomas) and GHD in 8.3% (8.9% in micro-, 7.8% in macroadenomas). About 30% of microadenomas had at least 1 pituitary deficiency at diagnosis, independently of tumor localization within the sellar region.


CONCLUSIONS
The presence of isolated hypoadrenalism suggests that the order of appearance of hypopituitarism does not always follow the one expected. Given the relatively high prevalence of isolated hypoadrenalism even in microadenomas, we suggest a full assessment of basal and dynamic pituitary function in all NFPA regardless of tumor size.
Endocrinology and Diabetology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
Giulia
G
Carosi
Elena
E
Malchiodi
Emanuele
E
Ferrante
Elisa
E
Sala
Elisa
E
Verrua
Eriselda
E
Profka
Claudia
C
Giavoli
Marcello
M
Filopanti
Paolo
P
Beck-Peccoz
Anna
A
Spada
Giovanna
G
Mantovani