Adrenal (131)I-6β-iodomethylnorcholesterol scintigraphy in choosing the side for adrenalectomy in bilateral adrenal tumors with subclinical hypercortisolemia

PURPOSE: Adrenal scintigraphy with 131I-6β-iodomethylnorcholesterol is considered by several authors the gold standard for assessing tumors with subclinical hypercortisolemia. However, most of the described series consist mainly of cases with unilateral lesions. The aim of our study was to assess whether scintigraphy is useful in choosing the adrenalectomy side in the case of bilateral adrenal tumors with subclinical hypercortisolemia. METHODS: The study focused on 15 consecutive patients with benign bilateral adrenal tumors and subclinical hypercortisolemia. The scintigraphy with 131I-6β-iodomethylnorcholesterol was performed. Fourteen patients underwent unilateral adrenalectomy; the gland with predominant uptake on scintigraphy was removed. Cortisol and ACTH concentrations were measured one and six months after surgery. Post-dexamethasone cortisolemia was assessed six months after surgery. To date, the patients have been under postoperative observation for 1–4 years. RESULTS: Four patients showed unilateral uptake of radiotracer, and nine patients showed predominant accumulation of radiotracer in one of the adrenal glands. The smaller tumor was predominant in 2 cases. Percentage of activity on the predominant side correlates positively with the difference between tumors’ diameters. Unilateral uptake of radiotracer predicts long-lasting postoperative insufficiency of the second adrenal gland. Excision of predominating tumor led to cessation of hypercortisolemia in all patients. CONCLUSIONS: The corticoadrenal scintigraphy is useful in choosing the side for operation in the case of bilateral adrenal tumors with subclinical hypercortisolemia.