Endocrine Abstracts

Background: There is a large agreement that most of the incidentally discovered, clinically mute adrenal masses are incidentalomas - non-functioning tumours, which have to be explored in order to differentiate the adrenal carcinoma.

Material and methods: We studied the prevalence and characteristics of clinically mute adrenal tumours and the evolution of adrenal incidentalomas, with the approval of the local Ethical Committee, in 123 patients with adrenal masses, hospitalised in the Neuroendocrine Department between 1992-2004: 63 patients with mute adrenal tumours, 60 with functioning adrenal tumours. The investigations included hormonal tests (plasma cortisol, urinary free cortisol, 17- HOCS, 17-KS, urinary and plasma metanephrine, dehydroepiandrosterone sulphate, 17 hydroxyprogesterone), plasma Na, K and imaging with computed tomography (CT).

Results: Clinically mute adrenal tumours were recorded in 24 patients aged under 50 years (representing 37% of all the adrenal tumours at this age) and in 39 patients over 50 years (representing 67%, respectively). Adrenal masses, with diameters of 1-9 cm (19% under 2 cm), were unilateral in 47 cases and bilateral in 16 cases. After evaluation, we recorded 1 asymptomatic Cushing's syndrome, 1 pheochromocytoma, 1 congenital hyperplasia, 5 carcinomas, 2 lipomas and 2 adrenal cysts. 7 patients had subclinical Cushing's syndrome (11%) and 10 had borderline urinary metanephrines (15.8%). Surgery in 16 patients revealed 3 pheochromocytomas, 1 adrenal carcinoma, 9 adenomas, 3 metastases. Twenty-two patients were followed-up for a mean of 32 months (5 -120 months): an increase of the tumour was recorded in 7 patients (33.3%), all with initial diameters >2 cm. In 66.7% of the cases, the tumours were unmodified.

Conclusions: Among 22 followed-up incidentalomas out of 63 mute adrenal tumours, only tumours over 2 cm size have increased. Long term follow-up of tumoral volume and secretion should enable us to indicate surgery only in cases with signs of evolution.