Silent Corticotroph and Somatotroph Double Pituitary Adenoma: A Case Report and Review of Literature

Introduction: Clinically silent double pituitary adenomas consisting of corticotroph and somatotroph cells are exceedingly rare clinical findings. In this report, we present the case of a double adenoma with sparsely granulated somatotroph and densely granulated corticotroph cells, the latter of which exhibited an elevated K i -67 labeling index. Case Presentation: A 28-year-old man presented to the clinic with a 1-year history of recurrent headaches. MRI of the brain with and without contrast revealed a 2.1 (anterior-posterior) × 2.2 (transverse) × 1.3 (craniocaudal) cm pituitary adenoma invading into the left cavernous sinus and encasing the left internal carotid artery. There was no optic chiasm compression noted. The patient was taken to the operating room for endoscopic transnasal resection without complications. Immunohistochemical staining of the tumor revealed a double adenoma consisting of distinct sparsely granulated somatotroph and densely granulated corticotroph cells that were positive for growth hormone (GH) and adrenocorticotropic hormone (ACTH), respectively. K i -67 index labeling revealed a level of 6% within the corticotroph adenoma. No increase in serum growth hormone or adrenocorticotropic hormone was found, indicating the presentation of a clinically silent double adenoma. Conclusion: Transsphenoidal surgery (TSS) remains a first line approach for clinically silent adenomas presenting with mass effects. However, increased rates of proliferative markers, such as the K i -67 index, have been found to provide useful insight into the clinical course of such tumors, both before and after treatment. Determining the K i -67 index of silent pituitary adenomas could be valuable in predicting recurrence after initial surgical resection and identifying tumors that are at an increased risk of needing additional therapeutic interventions or more frequent surveillance imaging ([ Figs. 1 ]–[ 3 ]). Fig. 1 Coronal T2-weighted contrast-enhanced MRI showing pituitary gland enlargement with resultant stalk deviation (arrowhead) and encasement of the internal carotid artery (arrow). Fig. 2 The corticotroph adenoma (left) shows diffuse cytoplasmic staining with CAM5.2, while the somatotroph tumor (right) shows distinctive fibrous body type staining. Fig. 3 Ki67 proliferative index is elevated in the corticotroph adenoma (~6%; left) and lower in the somatotroph adenoma (~1%; right). Publication History Article published online: 15 February 2022 © 2022. Thieme. All rights reserved. Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany