Prevalence of adrenal masses in Japanese patients with type 2 diabetes mellitus

Introduction: To date, there have been no reports on the prevalence of adrenal masses in type 2 diabetic patients. The present study aimed to evaluate the prevalence of adrenal incidentaloma in type 2 diabetic patients in Japan. Subjects: We retrospectively evaluated the presence of adrenal masses using abdominal CT scans in 304 type 2 diabetic patients. In those with adrenal masses, we examined the hormone production capacity of the adrenal mass. Results: Fourteen patients (4.6%) had an adrenal mass. Hormonal analysis identified one case as having subclinical Cushing's syndrome, two with primary aldosteronism. Eleven cases had non-functioning masses. Discussion: The reported prevalence of adrenal incidentaloma in normal subjects is 0.6-4.0% in abdominal CT scan series. Our results show a relatively high prevalence of adrenal tumors in diabetic patients. On the other hand, the frequency of functional adenoma in diabetic patients is 21.4%, which is similar to that of normal subjects. Conclusion: Although further studies are needed to evaluate the prevalence of adrenal tumors in diabetic patients, our data suggest that evaluation of the presence of adrenal masses may be needed in patients with type 2 diabetes mellitus.