Authors: Massimiliano Andrioli Francesca Pecori Giraldi Martina De Martin Agnese Cattaneo Chiara Carzaniga Francesco Cavagnini
Publish Date: 2009/03/18
Volume: 12, Issue: 4, Pages: 294-
Abstract
Differential diagnosis of ACTHdependent Cushing’s syndrome often presents major difficulties Diagnostic troubles are increased by suboptimal specificity of endocrine tests the rarity of ectopic ACTH secretion and the frequent incidental discovery of pituitary adenomas A 43yearold female reported with mild signs and symptoms of hypercortisolism and initial hormonal tests and results of pituitary imaging 7mm adenoma were suggestive for Cushing’s disease However inadequate response to corticotrophinreleasing hormone and failure to suppress after 8 mg dexamethasone pointed towards an ectopic source Total body CT scan visualized only a small nonspecific nodule in the right posterior costophrenic excavation Inferior petrosal sinus sampling revealed an absent centerperiphery ACTH gradient but octreoscan and 18FFDGPETCT failed to detect abnormal tracer accumulation We weighed results of the laboratory with those of imaging and decided to remove the lung nodule Pathology identified a typical ACTHstaining carcinoid and the diagnosis was confirmed by postsurgical hypoadrenalism In conclusion imaging may prove unsatisfactory or even misleading for the etiologial diagnosis of ACTHdependent Cushing’s syndrome and should therefore be interpreted only in context with results of hormonal dynamic testing
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