Ectopic Non-Functional Pituitary Adenoma: Case Report and Literature Review

Background: Ectopic pituitary adenomas (EPA) are rare adenomas located outside the sella turcica. First reported in 1909, they are thought to arise from incomplete migration of pituitary tissue from Rathke’s pouch through the craniopharyngeal canal. EPA are thus often found under respiratory epithelium and frequently involve sphenoid or clival bone. Tumors may be functional (e.g., ACTH, GH, TSH-secreting) and present with endocrinologic dysfunction. Non-functional EPAs are particularly rare and pose a unique diagnostic challenge. Methods: We present a case of a patient with a growing, non-functional EPA in the nasal septum and floor of the sphenoid sinus successfully treated with resection. Case Report: A 75-year-old male with prior aortic valve replacement and coronary artery bypass surgery was referred for a sinonasal mass and gradual cognitive decline. MRI identified a 2.2 × 2.6 × 1.5 cm mass along the sphenoid sinus floor extending to the nasal septum. CT neck and comparison to prior CT from 8 years earlier redemonstrated the mass with interval growth. Biopsy was consistent with pituitary adenoma. Notably, there was no connection between the EPA and sella turcica, with an intact sellar face and no bony opening on imaging. The patient was evaluated at our multidisciplinary pituitary clinic where treatment options were discussed including monitoring. He elected for endoscopic endonasal resection of the mass and exploration of the sella. Bilateral sphenoidotomies and a posterior septectomy were performed with gross tumor in the sphenoid sinus floor. The left sphenopalatine artery was sacrificed, and the sphenoid floor between bilateral vidian nerves was removed along with the keel and tumor. The sella was explored and noted to contain a normal pituitary gland. The patient had an uneventful recovery and was discharged on postoperative day 1. Final pathology was consistent with non-functional EPA with diffusely positive synaptophysin, chromogranin, CAM 5.2, and SF1 staining, but negative CK7, p40, S100, PIT, TPIT, FSH, LH, Prolactin, GH, TSH, and ACTH. Ki-67 positivity was