Authors: Richard J Auchus G Mastorakos T C Friedman G P Chrousos
Publish Date: 2014/04/02
Volume: 17, Issue: 6, Pages: 447-452
Abstract
We describe a patient with Cushing’s syndrome and metastatic small cell lung cancer The plasma ACTH concentrations were markedly elevated 916 pmol/L and the AM Cortisol did not suppress by 50 overnight after administration of 8 mg dexamethasone both consistent with the ectopic ACTH syndrome Immunohistochemical studies of a single metastatic tumor specimen however demonstrated an absence of ACTH and yet an abundance of corticotropinreleasing hormone CRH In addition radioimmunoassay of the patient’s plasma demonstrated persistently elevated CRH concentrations The majority of the plasma CRH immunoreactivity exhibited the same chromatographic mobility as synthetic r/h CRH 1–41 on HPLC Failure to evaluate the tumor tissue for the presence of ACTH and/or CRH would have led to the erroneous conclusion that this patient’s Cushing’s syndrome resulted from paraneoplastic ACTH production We conclude that immunoassay of plasma for both ACTH and CRH and perhaps immunostaining of tumor samples are required to distinguish between the ectopic ACTH and CRH syndromes
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