Adrenal incidentalomas: experience from a retrospective study in a Chinese population

Abstract

Background: With no generally accepted criteria for preoperative differential diagnosis between benign and malignant adrenal lesions, management of adrenal incidentalomas, especially those between 4 and 6 cm, remains controversial.

Patients and methods: Clinical details, radiological diagnosis, laboratory examination, intervention measures, and follow-up data were noted in 152 patients with adrenal incidentaloma hospitalized at a tertiary referral hospital in eastern China between July 1999 and February 2008. Pathologic diagnoses were analyzed in surgical cases.

Results: Of 143 surgical patients, the mean pathologic size of the tumors was 5.6 ± 3.2 cm (range 0.5 to 22.0 cm). The final benign pathologic diagnosis mainly included adrenocortical adenoma (31.3%), pheochromocytoma (18.8%), myelolipoma (16.7%), and ganglioneuromas (9.0%). The incidence of malignancy was 6.9%. Based on the size criterion of 6 cm, there was a significant difference between malignant and benign tumor groups (P=0.007), but based on the size criterion of 4 or 5 cm, there was no significant difference between the two groups.

Conclusions: In our experience, the incidence of malignancy in adrenal incidentalomas was generally low, but relatively high in adrenal incidentalomas >6 cm. Nerve cell tumors constitute a significant number of cases of adrenal incidentaloma. Overtreatment of nonfunctional incidentalomas <4 cm remains frequent in China, and close follow-up for this group is recommended. Factors such as radiologic characteristics and patient concern should be taken into account for nonfunctional incidentalomas between 4 and 6 cm (not including 6 cm), for which laparoscopic adrenalectomy is a reasonable option.