2008 Annual Meeting Abstracts
Adrenal Biopsy is Unhelpful in the Evaluation of Adrenal Incidentaloma : A Decade of Experience
Peter J. Mazzaglia, M.D., Jack M. Monchik, M.D..
Rhode Island Hospital, Providence, RI, USA.
Objective: Examine the role for percutaneous adrenal biopsy.
Design: Retrospective review
Setting: Tertiary referral center
Patients: All adult patients undergoing image-guided adrenal biopsy from 1997 to 2007.
Main Outcome Measure: Biopsy accuracy
Results: There were 163 biopsies performed on 154 patients, 95 males and 59 females. Mean age was 66 ± 12.5 years. Eighty-eight biopsies (53.4%) were performed in patients with a prior diagnosis of cancer. Forty-five (26.4%) were performed when an imaging study suggested previously undiagnosed cancer with a simultaneous adrenal metastasis. Thirty (20.2%) were performed for isolated adrenal incidentalomas. Rates of positive biopsy in these three groups were 70.6%, 69.0%, and 16.7%, respectively. Pre-biopsy evaluation for pheochromocytoma was performed in < 5% of patients with established or suspected non-adrenal malignancies, and 32% of patients with incidentalomas. In patients with isolated adrenal incidentaloma, a radiology report recommended biopsy 33% of the time, for characteristics inconsistent with benign adenoma. Of the isolated incidentalomas, there were 21 benign, 3 adrenocortical carcinomas, 2 pheochromocytoma, 2 non-diagnostic, 1 lymphoma and 1 sarcoma. Benign incidentalomas measured 4.2 ± 2.1 cm (range 1.4-10.7), and malignancies measured 9.3 ± 3.3 cm (range 5.3-14) (p < .05). All incidentalomas ≤ 5 cm (n=18) were benign. There were 4 false negative biopsies: 3 adrenocortical carcinomas and 1 pheochromocytoma.
Conclusions: Biopsy is unhelpful in patients with isolated adrenal incidentaloma. Despite atypical radiographic findings, all non-functioning nodules ≤ 5 cm were benign. The negative predictive value is unacceptably low, and cannot be relied upon to rule out malignancy. Biopsy’s value remains the diagnosis of metastatic carcinoma in patients with a non-adrenal primary, proven by the > 70% positive rate in this group.