Clinically silent chromaffin-cell tumors: Tumor characteristics and long-term prognosis in patients with incidentally discovered pheochromocytomas

Background: Chromaffin-cell tumors (CCT), a rare group of catecholamine producing endocrine neoplasms, are traditionally suspected and diagnosed in patients presenting with episodic hypertension, together with the classic triad of headache, sweating, and tachycardia. Asymptomatic CCT are increasingly diagnosed, frequently as "incidentalomas". We have conducted a multicenter retrospective study, to assess the characteristics of a group of patients with clinically silent CCT, compared with a group of patients with typical CCT. Methods: Forty-three consecutive patients with CCT (24 with silent and 19 with typical tumors) have been retrospectively studied for a period of up to 20 yr (between 1989 and 2009); clinical picture, biochemical tests, as well as topographic and functional assessment were analyzed at diagnosis and periodically following treatment. Surgical samples were reviewed for neuroendocrine markers and for signs of invasiveness. Results: Patients with clinically silent CCT were significantly older than the typical ones (56.3±3.4 vs 48.0±4.8 yr; p<0.05); 15 of them (63%) were completely asymptomatic, and 9 patients (37%) complained of non-specific abdominal symptoms. Hypertension was present in only 6 silent CCT patients (25%), it was well controlled [mean blood pressure (BP) 134/84 mmHg], and persisted after surgery in only 2 patients. Fourteen out of twenty-four silent CCT patients (58%) were managed pre-operatively with prophylactic combination of α and β blockade, despite normal BP values. Clinically silent CCT were larger than typical CCT (mean diameter of 5.2±2.3 cm vs 4.6±1.5 cm, p<0.05) and secreted higher amounts of normetanephrines. All clinically silent CCT patients were defined as "cured" after surgery. Conclusion: Clinically silent CCT are more prevalent than previously reported. With an adequate pre-surgical diagnosis and patient preparation, the prognosis of silent tumors is usually excellent.