Endocrine Abstracts

Introduction: Phaeochromocytomas (PHEO) are tumours of the chromaffin cells and are usually detected due to the typical symptom triad including headache, palpitations and sweating associated with persistent and/or paroxysmal blood hypertension. An increasing proportion of PHEO is incidentally discovered upon abdominal imaging.

Objective: To analyse the clinical characteristics of the incidentally discovered phaeochromocytomas.

Method: A retrospective analysis of the medical files of 58 consecutive patients diagnosed with PHEO in our clinic between 1983 and 2009.

Results: Fifteen PHEO (25.8%, nine women, six men) have been discovered upon imaging performed for reasons unrelated to a blood pressure abnormality (one of them during family screening for multiple endocrine neoplasia). Five of these patients (33%) were asymptomatic for PHEO and one other patient was normotensive. Only one patient (6.6%) had the classic symptom triad, eight patients (53.3%) had hypertension, with paroxysms in 6 out of 15 patients (40%). From the 43 patients in whom the diagnosis was suspected on clinical grounds (27 women, 16 men), 15 patients (34.8%) had the typical symptom triad (P<0.05 compared to incidentally detected PHEO) and 42 (97.6%) were hypertensive (P<0.01), with paroxysms in 39 out of 43 patients (90.6%, P<0.01). Patients with incidentally detected PHEO are older at diagnosis than patients with clinically suspected PHEO (52.2±13.5 vs 44.1±12.4 years, P<0.05), have larger tumours (5.5±2.3 vs 4.8±2.1 cm, P<0.05) and are less likely to have bilateral tumours (0 out of 15 patients versus 6 out of 43 patients, 14%) or malignant tumours (0 out of 15 versus 3 out of 43 patients, 7%). Urinary or free plasma metanephrines have been falsely normal at initial work-up in 3/43 patients with clinically suspected PHEO (7%) and in none of those with incidentally detected PHEO.

Conclusions: A significant proportion of patients with phaeochromocytoma (25% in our series) are detected incidentally upon abdominal imaging. Since almost half of them may be normotensive at diagnosis, screening for catecholamine hypersecretion in every adrenal incidentaloma is mandatory in order to identify oligosymptomatic phaeochromocytomas.