Abstract
The objective of the study was to assess the prevalence and clinical features of incidentally
discovered clinically non-functioning pituitary adenoma (CNFPA) and to analyze its
natural history. A multicenter retrospective study in patients diagnosed with incidental
CNFPA periodically followed-up in 3 specialized neuroendocrinology units from 1992
to 2015 was performed. Out of a total of 189 CNFPA patients, 57 cases (30.1%; 29 women;
age at diagnosis 55.8±16.7 years) were incidental. Most patients (n=55, 96.5%) were
diagnosed by magnetic resonance imaging (MRI). A sum of 71.9% (n=41) were macroadenomas;
2 of them (3.5%) were giant adenomas (≥4 cm). Patients with macroadenomas were older
than those with microadenomas (59.5±16.7 vs. 46.4±18.1 years, p=0.007). Macroadenomas
were more common in men (85.7% vs. 58.6%, p=0.023). Twenty-eight patients (49.1%)
showed suprasellar extension; of these, 19 were accompanied by chiasmatic compression.
Hypopituitarism was present in 14 (24.6%) patients; which was partial in 13 patients
(22.8%) and complete in one patient (1.8%). The gonadal axis was the most frequently
affected (n=13, 22.8%). Twenty four patients (42.1%) underwent surgery. Of the non-operated
patients, 26 patients could be evaluated morphologically after a median follow-up
of 15.5 months (interquartile range, 5.7–32.7 months). No significant changes were
found in the maximum tumor diameter at the end of follow-up (1.2±0.6 vs 1.2±0.7 cm).
The majority of CNFPAs evaluated (n=23, 88.5%) did not show any changes in size. In
2 cases (7.7%) tumor size decreased, and in one patient (3.8%) increased. In our series
of CNFPA patients, approximately one-third were incidental. These tumors were diagnosed
by MRI preferably from the 5th decade of life without sex predilection. Most of them
were macroadenomas, more commonly diagnosed in men and at an older age, compared to
microadenomas. The suprasellar extension with chiasmatic compression and hypopituitarism
were frequent at diagnosis. Most of the non-operated incidental CNFPAs remain with
stable tumor size over time, growth being an unusual event.
Key words
pituitary incidentaloma - clinically non-functioning pituitary adenoma - restrospective
- multicenter study
