Adrenomedullary
hyperplasia (AMH) with increased urinary excretion of
epinephrine is regarded as the earliest adrenal manifestation in
familial pheochromocytoma; however, pathogenetic mechanisms and morphogenesis involved in the development of sporadic adrenomedullary diseases are unknown as yet. We present 4 patients with clinical, biochemical, imaging, and morphological findings of sporadic unilateral adrenomedullary
hyperplasia cured by unilateral
adrenalectomy. All patients were hypertensive with intermittent
hypertensive crises, and with increased
catecholamine concentrations in urine and serum. Correct unilateral localization was achieved by 123-I-BG-scan (planar and SPECT) (n = 2) or cavovenous blood sampling with selective catheterization of both suprarenal veins (n = 2). Histomorphometric analyses revealed diffuse adrenomedullary
hyperplasia in all 4 specimens with significant increase of relative volume to 17.6% (controls, 8.7%), and of estimated medullary weight to 0.95 g (controls, 0.45 g); corticomedullary ratio (C:M) was decreased to 5.4 (controls, 11.2).
DNA histograms showed euploidy in all cases. In 3 patients,
DNA analysis revealed evidence of cell proliferation, but without increase to grade of
malignancy indices (0.101-0.523).
Adrenalectomy was performed preferentially by a translumbar approach; the operative and postoperative course was uneventful in all 4 patients. Blood pressure without
antihypertensive drugs returned to normal in 3 patients, in 1 patient to the upper normal limit.