Interference by spironolactone on adrenocortical scintigraphy and other pitfalls in the location of adrenal abnormalities in primary aldosteronism.

A case of primary aldosteronism is presented in which the CT scan was initially misleading, adrenocortical scintigraphy was rendered inaccurate by pharmacological interference of spironolactone, and selective adrenal venous sampling of aldosterone was technically difficult. When dexamethasone suppression adrenocortical scintigraphy was performed with attention to technical detail and exclusion of interference by spironolactone, the causative lesion was scintigraphically demonstrated. This finding was confirmed by the results of venous sampling and the correctly located tumor removed.