Objective: To assess the role of the adrenal cortical scintigraphy with 131-I Norcholesterol (I-COL) in the diagnosis and characterization of silent adrenal masses.
Methods: We selected 57 patients who underwent an adrenal scintigraphy with I-COL, 36 women and 21 men (mean aged: 62.5 years), and who were classified into two groups: Group I or Incidentalomas, 39 patients without signs or symptoms of adrenal disease in whom an adrenal mass is incidentally discovered during a CT or ultrasound scan; and a second group or Group II, 18 patients with history of cancer in whom an adrenal mass is discovered. We defined the following Scintigraphic patterns in relationship with the CT: Normal, concordant unilateral (CU) or exclusive; discordant unilateral (DU); concordant asymmetrical (CA) or prevalent; discordant asymmetrical (DA) and nonvisualization (NV). The final diagnosis was obtained with clinical, analytical, and radiological evaluation and in some cases surgery.
Results: In Group I, the diagnoses were: 17 adrenal masses without criteria of malignancy or hormonal overproduction (the Scintigraphic patterns were 10 CA, 5 normal and 2 CU), 9 Subclinical Cushing's syndrome (4 CU, 4 CA and 1 normal), 5 adenomas (all CU), 3 adrenal primary carcinomas, with no uptake in the scintigraphy, and 5 were other diagnoses. In group II, 14 patients had benign masses (all patterns were normal or concordant) and 4 patients metastases (3 discordant and 1 NV patterns). The follow-up time was at least one year.
Conclusions: The adrenal cortical scintigraphy with I-COL provides us information on the functional status of silent adrenal masses and it is an useful tool to distinguish benign from malignant lesions; for this reason we considered that it must be integrated in the diagnostic algorithm as a complement to other techniques.