Background: Co-existing Cushing's syndrome and primary aldosteronism caused by bilateral adrenocortical adenomas, secreting cortisol and aldosterone, respectively, have rarely been reported. Precise diagnosis and management of this disorder constitute a challenge to clinicians due to its atypical clinical manifestations and laboratory findings.
Case presentation: We here report a Chinese male patient with co-existing Cushing's syndrome and primary aldosteronism caused by bilateral adrenocortical adenomas, who complained of intermittent muscle weakness for over 3 years. Computed tomography scans revealed bilateral adrenal masses. Undetectable ACTH and unsuppressed cortisol levels by dexamethasone suggested ACTH-independent Cushing's syndrome. Elevated aldosterone to renin ratio and unsuppressed plasma aldosterone concentration after saline infusion test suggested primary aldosteronism. Adrenal venous sampling adjusted by plasma epinephrine revealed hypersecretion of cortisol from the left adrenal mass and of aldosterone from the right one. A sequential bilateral laparoscopic adrenalectomy was performed. The cortisol level was normalized after partial left adrenalectomy and the aldosterone level was normalized after subsequent partial right adrenalectomy. Histopathological evaluation of the resected surgical specimens, including immunohistochemical staining for steroidogenic enzymes, revealed a left cortisol-producing adenoma and a right aldosterone-producing adenoma. The patient's symptoms and laboratory findings resolved after sequential adrenalectomy without any pharmacological treatment.
Conclusions: Adrenal venous sampling is essential in diagnosing bilateral functional adrenocortical adenomas prior to surgery. Proper interpretation of the laboratory findings is particularly important in these patients. Immunohistochemistry may be a valuable tool to identify aldosterone/cortisol-producing lesions and to validate the clinical diagnosis.
Keywords: Adrenal venous sampling; Bilateral adrenal adenomas; Histopathology; Hypercortisolism; Primary aldosteronism.