NIH state-of-the-science statement on management of the clinically inapparent adrenal mass ("incidentaloma")

To provide health care providers, patients, and the general public with a responsible assessment of currently available data regarding the management of clinically inapparent adrenal masses ("incidentalomas").

A non-Federal, nonadvocate, 12-member panel representing the fields of medicine, surgery, endocrinology, pathology, biostatistics, epidemiology, radiology, oncology, and the public. In addition, experts in these same fields presented data to the panel and to a conference audience of approximately 300.

Presentations by experts; a systematic review of the medical literature provided by the Agency for Healthcare Research and Quality; and an extensive bibliography of incidentaloma research papers, prepared by the National Library of Medicine. Scientific evidence was given precedence over clinical anecdotal experience.

Answering predefined questions, the panel drafted a statement based on the scientific evidence presented in open forum and the scientific literature. The draft statement was read in its entirety on the final day of the conference and circulated to the experts and the audience for comment. The panel then met in executive session to consider these comments and released a revised statement at the end of the conference. The statement was made available on the World Wide Web at http://consensus.nih.gov immediately after the conference. This statement is an independent report of the panel and is not a policy statement of the NIH or the Federal Government.

The management of clinically inapparent adrenal masses is complicated by limited studies of incidence, prevalence, and natural history, including the psychologic impact on the patient who is informed of the diagnosis. Improvements in the resolution of abdominal imaging techniques combined with increased use of abdominal imaging suggest that the prevalence of clinically inapparent adrenal masses will continue to escalate. The low prevalence of adrenal cortical carcinomas and the relatively low incidence of progression to hyperfunction call into question the advisability of the current practice of intense, long-term clinical followup of this common condition. All patients with an incidentaloma should have a 1-mg dexamethasone suppression test and a measurement of plasma-free metanephrines. Patients with hypertension should also undergo measurement of serum potassium and plasma aldosterone concentration/plasma renin activity ratio. A homogeneous mass with a low attenuation value (less than 10 HU) on CT scan is likely a benign adenoma. Surgery should be considered in all patients with functional adrenal cortical tumors that are clinically apparent. All patients with biochemical evidence of pheochromocytoma should undergo surgery. Data are insufficient to indicate the superiority of a surgical or nonsurgical approach to manage patients with subclinical hyperfunctioning adrenal cortical adenomas. Recommendations for surgery based upon tumor size are derived from studies not standardized for inclusion criteria, length of followup, or methods of estimating the risk of carcinoma. Nevertheless, patients with tumors greater than 6 cm usually are treated surgically, while those with tumors less than 4 cm are generally monitored. In patients with tumors between 4 and 6 cm, criteria in addition to size should be considered in making the decision to monitor or proceed to adrenalectomy. The literature on adrenal incidentaloma has proliferated in the last several years. Unfortunately, the lack of controlled studies makes formulating diagnostic and treatment strategies difficult. Because of the complexity of the problem, the management of patients with adrenal incidentalomas will be optimized by a multidisciplinary team approach involving physicians with expertise in endocrinology, radiology, surgery, and pathology. The paucity of evidence-based data highlights the need for well-designed prospective studies. Either open or laparoscopic adrenalectomy is an acceptable procedure for resection of an adrenal mass. The choice of procedure will depend upon the likelihood of an invasive adrenal cortical carcinoma, technical issues, and the experience of the surgical team. In patients with tumors that remain stable on two imaging studies carried out at least 6 months apart and do not exhibit hormonal hypersecretion over 4 years, further followup may not be warranted.