131I-iodocholesterol (NP-59) scintigraphy in adrenocortical diseases

The diagnostic usefulness of adrenal imaging with 131I-iodocholesterol (NP-59) is now well established. In order to correlate histopathology with the adrenal scan the authors examine and report their experience in 37 patients with surgically proven adrenal lesions or pituitary adenomas. This series included 24 patients with Cushing's syndrome: 14 caused by benign adrenal adenoma and 10 due to bilateral pituitary-ACTH-dependent adrenocortical hyperplasia. Ten patients with primary aldosteronism were submitted to surgery which confirmed the presence of aldosterone-producing adrenal adenomas. Two women with hyperandrogenism (due to virilizing ovarian tumors) had normal adrenals but the ovarian stromal luteoma markedly concentrated the iodocholesterol while the arrhenoblastoma did not. A patient with adrenal hematoma is also included in this report. The overall histopathological correlation with the radiocholesterol scintiscan yields an accuracy in our series of 97% (36/37). The false-negative adrenal scan (also missed by other non-invasive techniques) occurred in a patient with an aldosterone-producing adrenal adenoma measuring 1.0 X 1.5 cm.