Endocrine Abstracts

The growing incidence of adrenal incidentaloma needs new methods of assessment of their function, especially for cases with subclinical hyperfunction. The bilateral adrenal incidentalomas in patients with subclinical Cushing syndrome (SCS) often need only unilateral surgery, but if their diameters and phenotypes are similar, coming to decision about side of adrenalectomy may be difficult. Another problem generate tumors suspected of subclinical aldosterone hypersecretion: the adrenal venous sampling is an invasive method and patients not always agree to it. Border values of cortisolaemia in dexametasone suppression test may also lead to hesitation about usefulness of adrenalectomy.

Iodomethyl-norcholesterol is a highly specific tracer for the functional characterization of the adrenal cortex and scintigraphy with it can be a useful additional tool for the treatment decisions in the cases described above.

We present series of Iodomethyl-norcholesterol scintigraphy performed in 25 patients. The indications for scintigraphy were: subclinical hypercortisolaemia in patients with bilateral adrenal tumors (18 cases), primary hyperaldosteronism (three cases) and uncertainty in assessment of cortex function (border results) (four cases). We used two different protocols, depending of assessed adrenal function (without dexametasone if were no doubt about SCS).

Scintigraphy confirmed unilateral adrenal hyperfunction in 12 of 22 patients with suspicion of SCS. In all operated patients in this subgroup, transient postoperative secondary insufficiency of the second adrenal gland was observed, confirming the diagnosis of SCS and proper choice of operating side. The scintigraphy in three patients with primary hyperaldosteronism confirmed the source of disorder. Two of these patients have already been operated with clinical and biochemical benefits.

Our observations indicated that adrenal scintigraphy may be the valuable method for adrenal tumor function assessment, which helps in decision about surgery in cases of subclinical adrenal hyperfunction and bilateral adrenal lesions.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.