Characteristics of adrenal incidentalomas: 5-year experience in Chi Mei Medical Center

With routine use of imaging techniques such as abdominal ultrasound, CT scan and MRI, incidentally discovered adrenal masses detected with increased frequency have been the focus of interest during the last 20 years. The definition of adrenal incidentaloma is for any adrenal mass discovered by a noninvasive abdominal imaging techniques performed for reasons other than suspected adrenal disease. Once an incidentaloma has been detected, a decision concerning its management is unavoidable. Although most adrenal incidentalomas are non-functional adenoma, but a substantial percentage of these incidentalomas are hormonally active tumor, such as cortisol-secreting tumor, pheochromocytoma, primary aldosteronism, and less frequently, adrenocortical carcinoma, which early diagnosis and treatment is critical. For the management approaches to adrenal incidentalomas, evidences support that screening for the autonomy and malignant potential by means of endocrine function tests and image phenotype is necessary. In this study, we collected the cases of adrenal tumor in recent 5 years, from January 1998 to December 2002, in Chi Mei Medical Center. The prevalence of adrenal incidentalomas in our hospital is approximately 0.18%, account for 49.6% of total cases of adrenal mass. Most adrenal incidentalomas are non-functional tumors, 4% of adrenal incidentalomas in our series are clinically silent but hormonally active endocrine tumors, which include 3% pheochromocytomas and 1% cortisol-secreting adenoma.