7460 An Atypical Presentation of a Nonfunctional Pituitary Macroadenoma Found in a Patient with Chronic Sinusitis

Abstract Disclosure: A.A. Patel: None. V.Q. Mai: None. Non-functioning pituitary adenomas (NFPAs) are benign pituitary tumors that account for up to one third of all pituitary adenomas. The vast majority of NFPAs are incidentally found on head or brain imaging performed to evaluate for other medical problems. We present a unique case of a NFPA incidentally found via biopsy during a sphenoid sinus endoscopy. A 56-year-old female was evaluated initially by otolaryngology for two year duration of persistent post-nasal drip, retro-orbital pressure and frontal headaches despite trials of antibiotics and allergy medications. A CT of the sinuses showed soft tissue opacification of the midline sphenoid sinus with erosion of the sellar floor. Nasopharyngeal endoscopic evaluation showed copious purulent material and granulation tissue from the floor of the sphenoid sinus which was drained and biopsied. Surgical pathology was consistent with pituitary adenoma. Immunohistochemical staining showed strong reactivity in the cells with chromogranin A, CD56, INSM1, and synaptophysin and scattered positivity with AE1/AE3 and FSH. E-cadherin staining was retained and p53 negative. ACTH, CD31, CD68, GH, LH, prolactin, and TSH were non-reactive. Biochemical evaluation demonstrated that the lesion was hormonally non-functioning. An MRI of the sella subsequently showed a pituitary macroadenoma measured 1.7 x 0.7 x 1.4 cm extending into the right cavernous sinus and inferiorly into the right sphenoid sinus and wrapping around the right internal carotid artery without compressing it. The patient was initially thought to have Ectopic Sphenoid Sinus Pituitary Adenoma (ESSPA) which is rare and accounts for only 2% of all pituitary adenomas. By strict definition, ESSPA does not often have direct anatomic connection with the pituitary and imaging studies usually show a normal pituitary gland. In our patient, MRI shows a direct communication and extension into the sphenoid sinus potentially following the migratory embryonic path during the Rathke's pouch development. Therefore, although not truly an ESSPA, this case may still be a unique variant where there is not a complete separation of the path between the pituitary and pharynx. Management options of NFPAs include observation, surgical resection if symptomatic or compressive, medical therapy with dopamine agonists and/or somatostatin agonists, or radiation therapy. Our patient was particularly unique as the endoscopy also resulted in surgical removal of part of the adenoma from the sphenoid sinus. She will be monitored for development of compressive symptoms and growth of her macroadenoma on subsequent imaging to determine the need for further surgery. In conclusion, it is important to broaden our differential diagnoses to include intracranial pathology particularly the pituitary gland when evaluating for common symptoms and chronic diseases of the sinuses. Presentation: 6/2/2024