Endocrine Abstracts

An increasing prevalence of incidental adrenal lesions (adrenal incidentalomas) has been reported in recent years. It is now estimated that adrenal incidentalomas can be found in about 4% of the general population by CT and in up to 10-15% at autopsy. Patients with neuroendocrine tumours (NETs) (including mainly GEP-NETs and pulmonary carcinoids) are expected to have an even higher prevalence of adrenal incidentalomas because of the known genetic preponderance in a subgroup of them (e.g. MEN1 syndrome) and the generally increased risk of second neoplasms postulated in this group. Therefore, the aim of this study was to estimate the prevalence of adrenal incidentalomas in patients diagnosed with NETs and to evaluate their clinical and radiological pattern. A group of 181 NET patients treated in one centre were retrospectively analysed (patients on somatostatin analogue therapy in the course of locally advanced or metastatic NETs). All patients underwent repeated abdominal CT (with initial assessment in an adrenal protocol) and clinical and laboratory evaluation (including serum cortisol and DHEA-S and urine methoxycatecholamine measurement). Of these, 26 (14.4%) had adrenal lesions (35 different lesions). The incidence was similar in women and men (13.6% and 15.4%, respectively). Among the 35 lesions, there were 27 adenomas (77.1%), 3 NET metastases (8.6%), 2 metastases of other origin (renal cell carcinoma; 5.7%), 2 pheochromocytomas (5.7%) and 1 myelolipoma (2.9%). The highest frequency of adrenal incidentalomas was observed in pulmonary NETS (7/20 patients, 35%). Adrenal incidentalomas were found in 15.1% of pancreatic (8/53 patients) and 11.7% of small bowel (7/60 patients) NETs. The prevalence of adrenal incidentalomas in patients with unknown primary NETs was also high - 25% (3/12). As expected, the frequency of adrenal incidentalomas was higher among MEN1 patients (6/9, 66.7%) compared to sporadic cases (20/171, 11.7%). Of the adrenal lesions, 92% were hormonally inactive. Progression in size over time was observed in 11.4% (4/35) of lesions, but only in 3.7% (1/27) of adenomas. The mean diameter of the lesions was 17.0 +- 10.6 mm, with 24 out of 35 (68.6%) located in the left adrenal gland. The prevalence of adrenal incidentaloma is relatively high in NET patients. However, after excluding MEN1 and other genetic syndromes such as VHL, the prevalence drops closer to the values observed in the general population. The majority of incidentally found adrenal lesions are hormonally inactive adenomas that do not exhibit significant growth over time.