Giant silent corticotrope pituitary adenoma in a patient with complicated clinical course

Abstract

Introduction Somatostatin analogues are a cornerstone in the treatment of acromegaly. Somatostatin analogues of the first generation, mainly targeting the somatostatin receptor (SSTR) subtype 2, proofed to be efficient in most patients with acromegaly. With the development of somatostatin analogues targeting the subtype 5 additionally to the subtype 2, i.e. pasireotide, an efficient drug for ACTH secreting pituitary tumors and suboptimal responding acromegaly patients became available. Methods We investigated immunohistochemically SSTR subtypes expression in three pituitary adenomas: two from operated acromegaly patients with clinical relapse and one from a patient with clinically silent ACTH-positive macroadenoma with unfavourable clinical course. Results The predictive value of SSTR subtypes immunhistochemical analysis for the therapeutic response was discussed. The one silent corticotroph adenoma case presented here was negative for subtype 2 as well as for subtype 5 and therefore we did not see an indication for somatostatin analogue therapy. In acromegaly high Ki-67 appeared to have a negative impact upon therapeutic response in the two cases. Conclusion The immunohistochemical analysis of SSTR subtypes expression in pituitary adenoma patients especially with acromegaly and complicated clinical course might be helpful for decision making or prognostic significance. Our case reports point to the need of clinical trials for further investigation.