MON-260 Sinonasal Papilloma Masquerading as a Pituitary Macroadenoma

Background: Sinonasal tumors are rare, with annual worldwide incidence of approximately 1 in 100,000, and are not commonly considered in the differential diagnosis of pituitary tumors (1). Sinonasal tumors are well known for their invasiveness, tendency to recur and association with malignancy. We present a case of sinonasal papilloma presenting as a large suprasellar mass. Clinical Case: A 61 year-old male with a past medical history including type 2 diabetes mellitus presented with chief complaints of headaches and visual disturbances over the past 6 months. Prior to admission he experienced episodes of left eye midline deviation associated with diplopia. New onset dysphagia associated with leftward tongue deviation prompted him to seek medical attention. The social history was notable for chemical exposures in his work at a hair salon; he is sexually active with his husband. He has had no sexually transmitted infections and has been vaccinated against human papilloma virus (HPV). CT of the brain showed a large sellar mass. A subsequent MRI of the pituitary demonstrated a large destructive mass centered on the clivus elevating the pituitary gland into the suprasellar cistern. The mass measured 6 cm x 4.5 cm in the axial plane with displacement without invasion of the cavernous sinuses. The mass extended anteriorly into the ethmoid sinuses and extended posteriorly into the prepontine cistern displacing the basilar artery. Pituitary hormonal analysis included a 250 mcg Cosyntropin stimulation test resulting with a random cortisol of <1.0 ug/dl rising to 17.7 ug/dl following Cosyntropin administration. Additional anterior pituitary results included FSH of 3.8 mIU/ml (1.5-14 mIU/ml), LH of 1.3 mIU/ml (1.4-7.7 mIU/ml), total testosterone of 230 ng/dl (300-700 ng/dl), and prolactin 11.1 ng/ml (2.6-13 ng/ml). Ophthalmology was consulted for visual field testing which proved normal, however a partial left cranial nerve VI palsy was noted likely secondary to cavernous sinus involvement. A biopsy of the sellar mass was obtained by bedside nasal endoscopy. The initial biopsy was consistent with a non-dysplastic, inverted sinonasal papilloma with negative HPV and P16 serologies. The patient underwent resection of the pituitary mass, with surgical pathology showing superficially invasive squamous cell carcinoma arising from sinonasal papilloma. Conclusion: This is one of the very few cases reported in the literature of a sinonasal papilloma masquerading as a pituitary mass. Sinonasal papilloma should be considered when evaluating large destructive suprasellar tumors. Although a benign tumor, the local aggressiveness of sinonasal papilloma and the potential to give rise to squamous cell carcinoma highlights the significance of identifying this lesion.