Is adrenal tumor size related to evolution time or does it represent a biological difference?]

Background: Adrenal tumor (AT) malignancy has been related to tumor size. Since laparoscopic surgery is being used, smaller adrenal tumors are being excised. Aim: To evaluate eventual clinical and histological differences between adrenal tumors smaller than 4 cm. and those larger than 6 cm. Patients and Methods:: Retrospective review Of pathological reports and clinical records of patients operated,for adrenal tumors, dividing them in two groups. Group 1 had 29 patients aged 52 +/- 13 years with AT < 4 cm operated during the period 2000-2005, and Group 2 was formed by 52 patients aged 46 +/- 18 years with AT >6 cm operated between 1984-2005. Tumors between 4 and 6 cm were not included in the study to establish clear cut differences between groups. Results: Tumors were functional in 40 and 41% of cases in groups 1 and 2 respectively. Fifty percent of functional tumors of group 1 were pheochromocytomas and the rest secreted aldosterone. In group 2, 66% of tumors were phechromocytomas and no aldosterone secreting tumors were found. Fifty two and eight percent of tumors in Groups 1 and 2 were adenomas, respectively (p <0.001). Nineteen tumors of group 2 were malignant. compared with one of group 1 (p <0.001). Conclusions: The tumor size of adrenal conical tumors may represent biological differences, suggesting two different tumor populations. At time of diagnosis adrenal carcinomas are almost always larger than 6 cm.