Characterization of the secretory profile of gonadotroph pituitary tumors.

Purpose: Gonadotroph pituitary tumors (GnPiT) represent 70-75% of clinically non-functioning tumors in surgical series. Their proportion has increased with the diagnostic use of transcription factors in addition to gonadotropin immunostaining, but the prevalence of functioning cases has not been re-evaluated. The aim is to provide a comprehensive, up-to-date characterization of GnPiT, including pathological subtyping and search for whispering/functioning cases (^w/fGnPiT).

Methods: A single-center retrospective study of patients who received a pathological diagnosis of GnPiT between 2020 and 2022. Clinical, hormonal, and pathological data were analyzed according to sex and age, with short-term post-operative re-evaluation. Histological subtypes were defined according to hormone immunostaining.

Results: 151 patients (103 M, 48 F) were studied. The diagnosis was incidental in 72 cases (48.0%). Age distribution at diagnosis was normal in males (median 63 years (25-89)), and bimodal in females (median age 58 years (26-84)). A single case of overt hyperfunction, revealed by ovarian hyperstimulation syndrome, occurred. The prevalence of likely ^w/fGnPiT was estimated at 6.0% (M: 7.7%, F: 2.1%) including nine cases showing characteristics consistent with pre-operative mild hormone secretion (1 F, 8 M). FSH hypersecretion was predominant, all but two ^w/fGnPiT had FSH/LH immunostaining. FSH/LH tumors were also the most prevalent in the whole series (63.6%) followed by FSH-, LH- and hormone-negative cases (27.1%, 4.0% and 5.3%, respectively). No significant differences in macroscopic or pathological characteristics were found among pathological subtypes.

Conclusion: Clinically relevant hypersecretion remains uncommon in GnPiT but may be under-evaluated. No significant differences in tumor behavior emerged among pathological subtypes.