Abstract #1406235: Silent Corticotroph Adenomas are More Aggressive than Other Nonfunctional Pituitary Adenomas

Silent corticotroph adenomas (SCAs) are immunopositive for adrenocorticotropic hormone (ACTH) but do not cause Cushing disease. They account approximately 20% of all and 5% nonfunctioning pituitary (NFAs). We present a case an SCA with extensive invasion outside the sella turcica causing pathology through mass effect on adjacent structures. A 48-year-old male was found to have 3.8 cm left cavernous sinus compression optic chiasm during evaluation headaches diplopia. No signs syndrome or acromegaly were apparent examination. Metabolic notable secondary hypothyroidism (TSH 0.7 mIU/L, 0.45-5.33; free T4 0.3 ng/dL, 0.5-1.3) hypogonadism (LH 2.2 1.2-8.8; total testosterone 105 270-1070), though serum prolactin (17.3 ng/mL, 2.6-13.2) IGF-1 levels (133 71-224) unremarkable. ACTH level increased multiple measurements (69.9-146.8 μg/dL, 7.2-63.3), 8 AM cortisol overnight dexamethasone suppression test only modestly elevated (1.9 expected < 1.8). The patient underwent transsphenoidal surgery (TSS) remove accessible tumor relieve symptoms effect. Histopathology adenoma low Ki-67 proliferation index (< 5%) 70-80% staining ACTH. Symptoms recurred 1 y later, imaging revealed substantial increase in volume residual tumor. Unfortunately, died from arterial bleeding second attempt at TSS. SCAs more aggressive than NFAs that fail stain intact hormone. Patients younger, likely female, greater likelihood diagnosis patients NFAs, proportion extrasellar extension is equivalent NFAs. progress recur same rate, time recurrence two-fold faster Recurrence rate unaffected by adjuvant radiation. as this be tumors limited Reduced expression mismatch repair gene MSH 6/2 may driver behavior SCAs. This illustrates small challenging subset propensity quickly typical NFA. Extensive poor prognostic sign recurrence.