Clinical features of silent corticotroph adenomas

Silent corticotrph adenomas represent a distinct pathological subtype of non-functioning pituitary adenomas that are traditionally believed to carry a more aggressive biological behavior and higher potential for recurrence. We conducted a retrospective review of all silent corticotroph adenomas treated and followed at our institution over the last 10 years. We reviewed clinical, radiological and pathological features. The series was compared to a matched cohort of ACTH-negative, non-functioning adenomas to compare clinical, radiological and pathological features. Our results were compared to the literature. Twenty patients met our inclusion criteria. Fifty-six percent of the patients were females. Mean age was 51 years (range 24-78 years). Visual dysfunction was the most common clinical presentation (38 %). Thirteen percent of the cases presented with acromegaly secondary to double adenoma (silent corticotroph adenoma and growth hormone adenoma) and 13 % presented with pituitary tumor apoplexy. All the tumors were macroadenomas. Frank cavernous sinus invasion occurred in 31 % of the cases. The patients who presented with acromegaly did not achieve remission postoperatively. In the remaining patients, recurrence occurred in 14 % of the cases over a mean follow-up period of 41 months. Compared to non-functioning adenomas, silent corticotroph adenomas were more likely to bleed (p value 0.014) and have double adenoma (p value 0.047). There was no difference in recurrence rates between silent corticotroph adenomas and non-functioning adenomas (p value 0.647). These results suggest that silent corticotroph adenomas have some unique features compared to non-functioning adenomas. Within the limits of our follow-up duration and sample size and our review of the literature, we would recommend that the traditional view to manage all silent corticotroph adenomas with adjuvant radiation should be reconsidered. We suggest adopting an initially more conservative follow-up surveillance and delay of upfront radiation until there is clear evidence of tumor recurrence.