Endocrine Abstracts

Background: Silent corticotroph adenomas (SCAs) are considered to be clinically silent and non-secreting but exhibit positive adrenocorticotropic hormone (ACTH) immunostaining. Whether, SCAs behave more aggressively than other non-functioning adenomas, remains controversial. We characterized our tertiary centre cohort of SCA patients, compared them to gonadotroph adenomas (GAs) and assessed for features predictive of recurrence.

Objective: To compare characteristics and outcomes of SCAs with GAs at a major tertiary centre.

Methods: We reviewed cases of SCAs operated by one neurosurgeon between January 2010 and January 2019 and matched them by age and sex to the GAs operated on by the same neurosurgeon in a 1:2 ratio.

Results: Our retrospective cohorts included SCAs (n=13) followed for median 57 months (range, 13-163 months) and GAs (n=26) followed for 72 months (range, 12-132 months). Compared to GAs, SCAs were of similar diameter (2.6 vs 2.0 cm, P=0.149) but had an increase in residual tumour size on radiological reporting in 38.5% cases compared to 19.2% among GAs. Intratumoral haemorrhage on pre-operative magnetic resonance imaging was reported in 53.8% of the SCAs and 11.5% of GAs (P=0.008). Higher mean pre-operative ACTH levels (44.7 vs. 23.0 ng/l, P=0.024) and lower mean post-operative prolactin (170.3 vs 305.6 mUI/l, P=0.032) were observed in the SCAs group. There was no perioperative mortality in either group. However, in the SCAs group 4/13 patients had significant immediate post-operative haemorrhage (two patients had acute subarachnoid haemorrhage predominantly in the suprasellar region, another had a large acute haematoma around suprasellar cistern requiring craniotomy; the last patient had significant sellar bleeding but good recovery postoperatively) whereas among the GAs, there was no post-operative haemorrhage. At one-year post-operative follow-up, 5/13 patients of SCAs had new onset secondary adrenal insufficiency compared to 1/26 in the GA cohort. During follow-up, all-cause mortality (non-pituitary surgery related) was higher among SCAs compared to GAs (30.8% and 19.2% respectively). Sex, tumour size, Ki67% indices and immediate post-operative cortisol measurement were not statistically found to be influencing the predictability of recurrence.

Conclusion: Our study shows that in the SCAs group, intratumoral haemorrhage was significantly higher and accompanied with greater risk of post-operative complications especially bleeding. A higher rate of deaths was observed in the SCA group but this needs to be confirmed in larger studies.