THU100 Case Of A Large Suprasellar-clival Mass: Prolactinoma Vs Paraganglioma

Disclosure: L.N. Madera Marin: None. Y. Rivera-Nieves: None. M.A. Ortiz-Rivera: None. A. Rosado-Burgos: None. L. El Musa Penna: None. W. Medina-Torres: None. L. Sepulveda-Garcia: None. M. Ramirez: None. L.A. Gonzalez-Rodriguez: None. M. Alvarado: None. N. Canales: None. Introduction Prolactin secreting adenomas comprise 30-40% of all pituitary adenomas. Generally, serum prolactin levels correlate with tumor size. Giant prolactinomas measure >4 cm, most have mass related clinical effects. Even large masses respond to cabergoline. Some may require surgical intervention. We present a case of a large pituitary mass associated with elevated prolactin levels, but with an interesting histopathologic analysis. Patient Description 30 y/o male patient with new onset decreased peripheral vision. Retinologist evaluation showed no abnormalities. Laboratories done by PCP found with altered thyroid function tests, but no treatment offered at the time. Two months later, the patient complained of worsening peripheral vision and was found with a left dilated pupil. A head CT scan was performed that showed a large brain mass. Admitted for urgent neurosurgery evaluation and high dose dexamethasone was initiated. ROS was remarkable for weight gain over the past year, and decreased morning erections, although denied decreased libido or erectile dysfunction. MRI showed an infiltrative skull base tumor extending from the clivus to the parasellar area encasing the left cavernous segment of the internal carotid artery with expansion of the sella obliterating the pituitary gland, and extension into the left optic canal. Pre-operative laboratories: Prolactin >877 ng/ml (2-17ng/ml), Cortisol 1.80 mcg/dL (4-22 mcg/dL), TSH 1.45 uIU/ml (0.4-4.0 uIU/ml), Sodium 142mMol/L (135-145mMol/L). Patient underwent left pterional craniotomy. Initial intra-operative pathology: “Positive for Neoplasia”. Post-operative laboratories: Prolactin >877 ng/ml, TSH 0.229 uIU/ml, FSH <0.30 mIU/ml (1.2-7.8 mIU/ml), and LH 0.16 mIU/ml (1.5-9.3 mIU/ml). Case Outcomes/Discussion Central hypothyroidism and hypogonadism confirmed, secondary hypocortisolism could not be assessed due to emergent corticosteroid infusion upon admission. A presumptive diagnosis of a giant prolactinoma was made for which cabergoline therapy was initiated. Final pathologic diagnosis revealed a paraganglioma. Urine fractionated metanephrines and catecholamines were normal. Immunostaining for prolactin requested. Paragangliomas arise from neuroendocrine cells, from either sympathetic or parasympathetic ganglia and can be solitary or multiple. Skull base and neck paragangliomas are usually benign while ∼20% of abdominal paragangliomas (sympathetic) are malignant. Anterior skull base paragangliomas are predominantly located in the sella and are rare but have been described in the literature. Very rare cases of pheochromocytomas or paragangliomas associated to pituitary adenomas have been reported. It has been named as the three P association, thought to be related to succinate dehydrogenase B and D mutations. Moreover, there are no cases in the literature of paragangliomas secreting prolactin. Presentation: Thursday, June 15, 2023