Adrenal masses which are found unexpectedly with US or CT examination of abdomen are called adrenal incidentalomas. The aim of study was to evaluate the contribution of imaging characteristics of incidentally discovered adrenal mass to the differential diagnosis.
We have studied 60 patients with adrenal mass (21 M, 39 F, age 3485 years) who had CT scan of abdomen for various diagnoses but they were not suspected to have adrenal pathology. The right adrenal gland was solitary affected in 20 cases, left in 28 cases and both adrenals in 12 cases. To determine the endocrine status of adrenal mass the usual tests for Cushings syndrome and pheochromocytoma were performed. The aldosterone/PRA ratio was measured in hypertensive patients. The benign character of adrenal mass was confirmed operatively or by follow up of tumor size for >1 year and lately washout test was used.
Results: None of our patients had Cushings syndrome or primary hyperaldosteronism. The non-functioning adrenal adenoma was confirmed in 45 patients, subclinical hypercortisolism had 5 patients, metastases to adrenal glands were found in 5 patients, two patients had lymphoma, myelolipoma 2 patients and one patient had asymptomatic pheochromocytoma. The density of metastases on plain CT images was >2045 HU and myelolipomas had density minus 70 HU. The adrenal adenomas had low precontrast density in 100% cases. Most of adenomas showed low contrast enhancement but 8/50 adenomas (16%) enhanced over 55 HU (5590 HU). Adenomas larger than 3 cm were found in 17/50 cases (34%).
Conclusion: From the imaging point of view the low density of lesion seems to be more important sign for the determination of the nature of lesion (myelolipoma, adenoma, malignancy) than the size of adrenal mass. We recommend CT scans in long-term followed-up patients for 3 years minimally once a year.
30 Apr - 04 May 2011
European Society of Endocrinology