Cross, Ashton E

Abstract Disclosure: B. Bahrani Fard: None. N. Nikravangolsefid: None. J. Maroun: None. A. Cross: None. T. Foster: None. T. McKenzie: None. W. Young Jr: None. B.M. Dy: None. M. Lyden: None. I. Bancos: None. Background: Giant pheochromocytomas (PHEO), defined based on size > 10 cm, are rare. Data on clinical presentation, management, and prognosis of giant PHEOs are scarce. Objectives: to determine prevalence of giant PHEO and compare presentation, management, and outcomes of patients with giant vs non-giant PHEOs. Methods: We conducted a single-center retrospective cohort study of consecutive patients with giant PHEO and randomly chosen patients with non-giant PHEO (referents) at 6:1 ratio, evaluated between 2000-2023. All variables were extracted from the electronic medical record. Results: Of 828 patients with PHEO evaluated between 2000 and 2023, 31 (3.7%) had giant PHEO (median size 12 cm, IQR 10.0-13.5). In comparison to referents (n=186, median size 4 cm, IQR, 2.9-5.0), patients with giant PHEO were similar in age (median age 53 vs 55 years, P=.55), more frequently discovered based on symptoms (52% vs 32%, P=.04), and less likely to be bilateral (3% vs 12%, P=.31). Genetic testing was performed in 103 (48%) of patients, without group differences, however, patients with giant PHEO were less likely to have an associated germline mutation detected (7% vs 47%, P=.004). Patients with giant PHEO had more symptoms of catecholamine excess (median of 2 vs 1, P=.04) and presented with a higher prevalence of severe metanephrine excess >10 times above upper normal range (76% vs 30%, P<.0001). Adrenalectomy was performed in 94% of patients with giant PHEOs and in 100% referents, with higher rates of open adrenalectomy in giant PHEO (86% vs 14%, P<.0001). In addition to preoperative alpha-adrenergic blockade (89%), metyrosine was used in 14 (7%) patients, mostly in patients with giant PHEO (26% vs 3%, P<.0001). Patients with giant PHEO had a longer hospital length of stay (laparoscopic: median 5 vs 2 days, P<.0001; open: median 6 vs 5 days, P=.24), and a higher complication rate (31% vs 10%, P=.006).Median follow up was 3 years (IQR 1-8) years, similar in patients and referents. Metastases developed at a much higher rate in patients with giant PHEOs (45% vs 4% in referents, P<.0001). Disease specific mortality was 7% in patients with giant PHEOs and 0% in referents. Conclusion: Patients with giant PHEO were more symptomatic, had a higher degree of catecholamine excess, and a higher rate of perioperative complications. Almost half of patients with giant PHEO developed metastases, warranting a close follow-up. Presentation: 6/2/2024

Abstract Context Data on giant pheochromocytomas (PHEOs), defined based on size 10 cm or greater, are scarce. Objective This work aimed to compare presentation, management, and outcomes of patients with giant vs non–giant PHEOs. Methods A retrospective cohort study was conducted in a referral center from 2000 to 2023. Consecutive patients with giant PHEOs and randomly chosen patients with non–giant PHEO (referents) were studied at a 1:6 ratio. Outcomes included perioperative complications, metastases, and mortality. Results Of 828 patients with PHEOs, 31 (3.7%) had giant PHEO (median size 12 cm, interquartile range [IQR] 10.0-13.5 cm). In comparison to referents (n = 186, median size 4 cm, IQR, 2.9-5.0 cm), patients with giant PHEO had more symptoms of catecholamine excess (median of 2 vs 1; P = .04) and presented with a higher prevalence of severe catecholamine excess (76% vs 30%; P < .0001). Adrenalectomy was performed in 94% of patients with giant PHEOs and 100% of referents. In addition to preoperative α-adrenergic blockade (89%), metyrosine was used in 14 (7%) patients, mostly in patients with giant PHEOs (26% vs 3%; P < .0001). Patients with giant PHEOs had a higher perioperative complication rate (31% vs 10%; P = .004). During a median follow-up of 3 years, metastases developed at a higher rate in patients with giant PHEOs (45% vs 4% in referents; P < .0001). Disease-specific mortality was 7% in patients with giant PHEOs and 0% in referents (P = .02). Conclusion Patients with giant PHEOs compared to referents were more symptomatic, had a higher degree of catecholamine excess, and had a higher rate of perioperative complications. Almost half of patients with giant PHEOs developed metastases, warranting close follow-up.