Adrenocorticotropin-producing pituitary adenoma detected with ^99mTchexakis-2-methoxy-isobutyl-isonitrile single photon emission computed tomography. A case report

Abstract

© 2015, Acta Endocrinologica Foundation. All rights reserved. Cushing’s disease (CD) is an adrenocorticotropic hormone (ACTH) mediated multisystemic state of adrenal hypercortisolism. An ACTH secreting benign pituitary tumor (adenoma) is the most common cause in the majority of patients with CD. Case report. This article describes a case of a 56-year-old woman presenting with clinical manifestations of hypercortisolism, with high plasma cortisol and ACTH levels that was suppressed with high-dose dexamethasone administration, suggestive of CD. Pituitary magnetic resonance imaging (MRI) of the sellar region was inconclusive. During the single photon emission computed tomography (SPECT) examination, an increased accumulation of technetium,99m, hexakis, 2, methoxy, isobutyl-isonitrile (99mTc-MIBI) in the pituitary gland area was noticed. Finally, response to corticotropinreleasing hormone (CRH) and ghrelin stimulatory testing, differentiated CD from ectopic ACTH and primary adrenocortical hypersecretion. Conclusion. We highlight the potential of99mTc-MIBI SPECT as sensitive and specific method of pituitary gland adenoma detection in patients with Cushing’s disease, when MRI fails to directly detect an adenoma and stimulatory tests with CRH and ghrelin are not in routine diagnostics.