SAT312 CT-guided Cryoablation Of Hereditary Pheochromocytoma

Disclosure: E. Griffing: None. B. Reading: None. F. De Luca: None. Background: Guidelines surrounding the management of hereditary pediatric pheochromocytomas (PHEO) are lacking. This is the first report of a pediatric patient with bilateral hereditary PHEO treated with right adrenalectomy and computed tomography (CT) percutaneous-guided cryoablation (CRA) of the left-sided lesion.Clinical case: A previously healthy 15 years-old male presented to a tertiary care hospital with a months-long history of episodic chest pain, flushing, shortness of breath, diaphoresis, and tremulousness. Paternal family history was significant for PHEO and brain stem hemangioblastoma in grandmother and PHEO in the great-grandfather. Targeted familial mutation analysis of the von Hippel-Lindau tumor suppressor gene was positive for pathogenic mutation c.500G>A (p.R167Q). Plasma free normetanephrine level was 4,625 pg/mL (nl: <145 pg/mL), while free metanephrines were normal. Magnetic-resonance imaging of the abdomen visualized a 4.4 x 3.4 x 5.3 cm right adrenal mass and a 1.4 x 1.4 x 1.4 cm left adrenal mass, consistent with bilateral PHEO. He underwent right adrenalectomy after initiation of alpha-receptor blockade and later addition of beta-receptor blockade due to heart rates in the 150’s. After discussion with parents, it was decided to observe the smaller left-sided adrenal lesion. Plasma free normetanephrines initially decreased to 338 pg/mL, but then increased to 507 pg/mL five months post-operatively. Six months after surgery, due to the persistence of hypertension with systolic blood pressure in the 140’s as well as tachycardia with heart rates in the 150’s, he underwent CT-guided CRA of the left-sided PHEO. A 12-minute freeze, 5-minute thaw, and 10-minute freeze, followed by an active thaw were performed. There was an increase in blood pressure during the initial thaw with systolic blood pressure in the 230s, accompanied by bradycardia to the 30s, treated with nitroprusside, phentolamine, and increased sedation. He required continuation of nitroprusside infusion for five hours post-procedure. He was discharged the following day with normal blood pressure and heart rate. He was able to completely wean off anti-hypertensive medications within one month and symptoms of chest pain and tachycardia resolved. In the four years since his procedure, he has not had a recurrence of PHEO nor development of adrenal insufficiency. Plasma free normetanephrines and metanephrines have remained within normal limits. Conclusion: Percutaneous ablation of hereditary PHEO has not been reported before in the pediatric population and may represent a novel treatment strategy that reduces the risk of adrenal insufficiency. Presentation: Saturday, June 17, 2023