Endocrine Abstracts

Introduction: It is known that many patients with adrenal incidentaloma display altered glucose tolerance. However, to our knowledge, we have no reports of the frequency of adrenal tumor in Japanese type 2 diabetic patients. We investigated the frequency of adrenal tumor in these patients.

Subjects: We evaluated the presence of adrenal tumor in 245 Japanese type 2 diabetic patients (mean age 60.8±13.4 years). The patients who were diagnosed malignant tumor and adrenal tumor previously were excluded.

Results: Nineteen patients (7.8%; mean age 62.0±13.6) had adrenal mass determined by abdominal CT scan (Bilateral, right and left were 4, 8 and 7, respectively). The mean size was 14.1±10.0 mm (maximum and minimum size were 55.0 and 1.0 mm, respectively). The properties of all adrenal masses were homogenous, and no cysts and calcification were observed. Measurement of plasma ACTH, renin activity, cortisol, aldosterone, DHEA-S and catecholamines, and 1 mg overnight dexamethasone suppression test were performed for diagnosis of functional adenoma. These adrenal masses were described as subclinical Cushing syndrome (SCS) and primary aldosteronism (PA) with SCS were 1 case for each, and 2 cases were PA. Fifteen were non-functioning tumor.

Discussion: It is reported that the frequency of adrenal incidentaloma in normal subjects was 3–4%. In our results, a relatively high prevalence, 7.8%, of adrenal tumor was observed in Japanese type 2 diabetic patients. On the other hand, the frequency of functional adrenal adenoma in diabetic patients was ~25% which was similar those in normal subjects.

Conclusion: Although further studies are needed to evaluate the frequency of adrenal tumor in type 2 diabetic patients, a relatively high prevalence of adrenal tumor was found in our study. Therefore our data suggest that adrenal tumor should be evaluated positively in type 2 diabetic patients.