Dual bronchial carcinoids and Cushing's syndrome with a paradoxical response to dexamethasone and a false positive outcome of inferior petrosal sinus sampling.

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Bibtex

@article{a80f55d10cdb4a588f4d0e7eade95140,
title = "Dual bronchial carcinoids and Cushing's syndrome with a paradoxical response to dexamethasone and a false positive outcome of inferior petrosal sinus sampling.",
abstract = "Objective Establishing the cause of Cushing's syndrome can be a considerable challenge, in particular in ectopic ACTH syndrome, and often requires a combination of biochemical tests and imaging procedures. Subject A 27-year-old man presented with signs of Cushing's syndrome. P-ACTH levels were 3 times above the ULN and free urinary cortisol in the order of 1900 nmol/24 h. The work-up showed remarkable results. Results A 2-day low-dose dexamethasone suppression test demonstrated paradoxical increases in cortisol. Sampling from the inferior petrosal sinuses (BIPSS) showed a central to peripheral ACTH ratio of 4.7 after CRH stimulation, i.e. indicated pituitary disease, but MRI of the pituitary was normal and baseline P-CRH <1.0 (ref. <5) pmol/L. CT scan of the lungs showed 2 oval-shaped masses, 1.3 x 1.8 and 1.3 x 2 cm, in the middle lobe. Both were positive at somatostatin receptor scintigraphy, compatible with tumors or inflammatory lesions. Subsequently, 11C-5-hydroxytryptophan-PET showed distinct uptake in the tumors but not elsewhere. Two carcinoids situated 3 cm apart, both staining for ACTH, were removed at surgery. Conclusion This unusual case with dual bronchial carcinoids inducing hypercortisolism illustrates the problems with identifying the source of ACTH in Cushing s syndrome. Possibly, the false positive result at BIPSS reflects an unusual sensitivity of the pituitary corticotrophs to CRH in this patient since ectopic CRH secretion and/or eucortisolism at the time of the procedure could be ruled out. The work-up illustrates the great value of 11C-5-hydroxytryptophan-PET as a diagnostic procedure when other investigations have produced ambiguous results.",
author = "Pia Burman and {\AA}saLinda Lethagen and Krasnodar Ivancev and Leif Johansson and Anders Sundin",
note = "The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Pediatrics/Urology/Gynecology/Endocrinology (013240400), Pathology, (Lund) (013030000)",
year = "2008",
doi = "10.1530/EJE-08-0385",
language = "English",
volume = "159",
pages = "483--488",
journal = "European Journal of Endocrinology",
issn = "1479-683X",
publisher = "Society of the European Journal of Endocrinology",

}