Endocrine Abstracts

Introduction: Giant pheochromocytomas (PCs) are adrenal tumors greater than 7 cm. The incidence and presentation of these large tumors is not well known, with only a few case reports published in literature. The preoperative and surgical management of giant PCs is also not well established.

Material and methods: A retrospective monocentric study at a tertiary center of 80 consecutive patients operated for a PC between 1988 and 2018.

Results: Among the 80 patients, 20 (25%) had a giant PC (mean tumor diameter of 9.9 cm). There was no difference in the clinical manifestations at diagnosis of these patients compared to patients with a smaller tumour. A significant proportion of patients with giant PC had hypertension (17/20) and half had diabetes. The diagnosis was made because of PC-related symptoms in half of the patients, mass symptoms in 5 patients (25%), during familial genetic screening in 2 (10%) and incidentally in only 1 case. Giant PCs presented higher levels of 24-hour urine metanephrines (P=0.028) and normetanephrine (P=0.001) compared with tumors of less than 7 cm. Interestingly, noradrenergic PCs were the largest tumors (P<0.01). The rate of perioperative haemodynamic (P=0.008) and surgical complications (P=0.032) was influenced by tumor diameter. When comparing patients with preoperative alpha-blocker treatment, there was no difference in cumulative dose according to the tumor size. As expected, giant PCs were more likely to have an open surgery (17/20; 85% vs 14/60; 23%). Also, giant PCs presented a higher rate of recurrence (P=0.039) and malignant behaviour (P<0.001).

Conclusion: We show that giant PCs are usually symptomatic and their presentation is not different from average-sized PCs, but they have a higher rate of perioperative hemodynamic and surgical complications and exhibit a more aggressive phenotype, thus requiring multidisciplinary management in an expert center.