Although primary hyperaldosteronism is an uncommon cause of hypertension, it is the most common form of renin-independent hypermineralocorticoidism. The plasma aldosterone concentration and PRA with orthostatic test and saline infusion test are very useful aids to make a diagnosis. In this case the inconsistency between hormonal data and morphologic images (TC and NMR) led us to a dilemma: it was a question of adrenal adenoma or hyperplasia? Because it was impossible to dose the 18-OH-corticosterone, we had to perform a iodocholesterol scintigraphy NP 59. To distinguish an hyperplasia as cause of this kind of hyperaldosteronism made us able to define a therapeutic program useful to hypertension control.