Accuracy of fine-needle aspiration cytology, CT-scan and MRI in patients with incidentally discovered adrenal masses

Objective: The aim of this study was to compare the usefulness of CT-scan, MRI, and FNA cytology in patients with incidentally discovered adrenal masses. Design: Thirty-four consecutive patients (6 men (17.6%) and 28 women (82.2%), median age of 47 years, range 26-80) with nonfunctioning adrenal masses of 2 cm or more in the greatest diameter (median 3.5 cm, range 2-9) were enrolled in the study. Methods: All patients underwent both CT-scan, MRI, and image-guided FNA cytology using spinal-type narrow-gauge needles prior to further procedures. Nineteen (55.9%) patients underwent adrenalectomy. Results: Final pathology showed 13 (38.2%) benign adrenal lesions, 4 (11.7%) adrenocortical carcinomas, and two (5.9%) unsuspected adrenal metastases. Fifteen (44.1%) patients who did not have surgery were considered definitively as having benign adrenal lesions since the mass was unchanged on CT scans performed during a median follow-up of 16 months. The sensitivity, specificity, and positive predictive value, negative predictive value , and accuracy were 67%, 86%, 50%, 92%, and 82% for CT-scan, 83%, 93%, 71%, 96%, and 91% for MRI, and 83%, 100%, 100% (p<0.05), 96%, and 97% for FNA cytology, respectively. Conclusions: Image-guided FNA cytology is a safe and sensitive procedure that may reveal unsuspected adrenal malignancies, may be useful for planning the follow-up of patients, and should be performed in all patients with incidentally discovered adrenal masses of more than 2 cm in size.