Portrait of a Series of Patients with Pheochromocytoma/Paraganglioma from a Refer-ence Center in Brazil: Relevance of Prior Background Features.

Pheochromocytomas (Pheo) and paragangliomas (PGL) are catecholamine-secreting tumours, whose functionality is confirmed by elevated plasma (Pl) and/or 24-h urinary (Ur) metanephrines (MN). Relevance of prior background features were reviewed in a large cohort of patients with Pheo and PGL. We reviewed clinical, hormonal, and imaging aspects of 116 patients studied prospectively: 93 Pheo; 22 PGL; one Pheo plus PGL. Twenty-five % PPGL were discovered incidentally. Systemic arterial hypertension (SAH) was present in 81% (43% on stage 3), whereas 9.5% were prehypertensive and 9.5%, normotensive. SAH plus paroxysms occurred in 31 (32.9%) patients, being exclusively sustained in the remaining; 26 (28%) had resistant SAH. Orthostatic hypotension was seen in 65% of patients. Pl/Ur MN and normetanephrine (NMN) were compared to those of a positive (56 functioning PPGL) and a negative control group (654 subjects with normal MN/NMN). Total and fractionated Ur MN were elevated in 94% PPGL patients. Cut-off values of 885 mcg/24-h for Ur MN, and of 1.5 nmol/L for Pl MN identified functioning lesions with 100%/100% sensitivity and 93%/97% specificity, respectively. MRI detected 56% right-side Pheo, 25% on the left, and 19% bilateral; PGL were 56.5% (13/23) retroperitoneal and 43.5%, cervical (10/23). Right-side Pheo were larger (5.8 cm) than left-side ones (3.7 cm), but retroperitoneal (6.5 cm) and neck PGL (6.9 cm) were similar. Tumour size positively correlated with total Ur MN. in this large cohort of PPGL patients we highlighted relevant aspects of SAH, the frequently overlooked manifestation of orthostatic hypotension, common incidental presentation, significant tumour size/hormonal production.