THU108 Pituitary Carcinoma Diagnosed After Ten Years Of Smoldering Ectopic Nasopharyngeal Cushing’s

Disclosure: L. Carafone: None. E. Vates: None. M. Johnson: None. I. Shafiq: None. Introduction: Pituitary carcinomas are rare and typically carry a poor prognosis. Diagnosis of pituitary carcinoma is made when there is metastasis to one or more sites distant from the pituitary, including craniospinal or systemic metastases. Clinical Case: A 54-year-old man presented to the endocrine clinic in 2011 with recurrent urinary tract infections, thoracic compression fractures, uncontrolled hypertension with hypokalemia, and weight gain. Examination revealed facial plethora, supraclavicular fat pad, central obesity, multiple ecchymoses, proximal muscle weakness and muscle atrophy of the upper and lower extremities. Workup demonstrated abnormal 1 mg overnight dexamethasone suppression test (cortisol after 1 mg dexamethasone 25.7 mcg/dL, n≤1.8 mcg/dL), elevated salivary cortisol (4340 and 2950 ng/dL, n≤99 ng/dL), elevated 24 hr urinary-free cortisol (271.7 mcg/24hr, n≤60 mcg/24 hr), and elevated ACTH (240 pg/mL, n≤46 pg/mL). MRI brain showed a large, lobulated mass in the sphenoid sinus adjacent to the inferior left lateral aspect of the pituitary fossa. He underwent surgical resection of the mass and pathology was consistent with pituitary adenoma, corticotroph cell type. Following surgery, laboratory studies showed normal salivary cortisol (<50 ng/dL, n≤99 ng/dL) and 24 hr urinary-free cortisol (22.4 mcg/24hr, n≤60 mcg/24 hr). After two years of sustained remission, he experienced local recurrence for which he underwent repeat surgery with subsequent remission. One year later, this was again followed by recurrence for which he was treated with intensity-modulated radiation therapy and medical therapies including cabergoline, ketoconazole and eventually metyrapone. Six years after the second surgery, MRI showed increasing heterogeneous enhancement at the postoperative site, and he underwent a third surgery with tumor resection and the same pathology results as the initial resection. He was subsequently treated with fractionated proton therapy. He continued to require metyrapone to manage hypercortisolism despite reassuring serial MRI scans. A right neck mass was palpated in 2022 and CT demonstrated a right level 2b lymph node measuring 2.3 x 1.8 x 2.3 cm. FNA revealed neoplastic cells and he underwent right neck dissection with excision of the lymph node. Pathology was consistent with pituitary tumor, corticotroph cell type. Given metastasis of the pituitary tumor to a cervical lymph node, a diagnosis of pituitary carcinoma was made. Conclusion: The time course in pituitary carcinoma is highly variable from the initial diagnosis of the pituitary tumor to the diagnosis of metastatic disease. In this case, the diagnosis of pituitary carcinoma was made nearly one decade after the initial identification of a pituitary tumor. Metastatic disease should be considered in aggressive pituitary tumors when biochemical and radiologic findings are discordant. Presentation: Thursday, June 15, 2023