Isolated Langerhans cell histiocytosis in an adult with central diabetes insipidus: case report and review of literature.
OBJECTIVE
To report a case of ectopic adrenocorticotropic hormone (ACTH) syndrome (EAS) in a patient with two distinct neuroendocrine tumors and to highlight the difficulties of establishing the differential diagnosis of EAS.


METHODS
We describe the clinical presentation of the current case, discuss its management, and report the results of molecular studies undertaken to determine whether the two tumors had a common origin.


RESULTS
A 52-year-old woman presented with obvious features of Cushing's syndrome. Findings on hormonal evaluation were consistent with EAS. Pituitary magnetic resonance imaging revealed normal findings. Computed tomographic imaging disclosed two masses, one in the lung and one in the pancreas. Somatostatin receptor scintigraphy showed uptake only in the pancreatic mass, which was surgically removed. It was a well-differentiated neuroendocrine tumor, with negative immunostaining for ACTH. Hypercortisolemia did not resolve after removal of the pancreatic tumor. The lung mass was subsequently excised, and pathology examination showed a carcinoid tumor with immunostaining for ACTH. Thereafter, plasma ACTH became immeasurable. The two tumors had similar patterns of X-chromosome inactivation; thus, whether they arose independently could be neither confirmed nor excluded.


CONCLUSIONS
This case demonstrates that, in the presence of more than one neuroendocrine tumor, somatostatin receptor scintigraphy may misguide the decision regarding the appropriate surgical course in patients with EAS, and it highlights the need for accurate studies to determine the source of ACTH in patients with EAS.
Ouyang
Daniel L
DL
Department of Medicine, Stanford University School of Medicine, Stanford, California, USA.
Roberts
Brian K
BK
Gibbs
Iris C
IC
Katznelson
Laurence
L
D020790:Diabetes Insipidus, Neurogenic / Q000150:complications* / Q000175:diagnosis; D006646:Histiocytosis, Langerhans-Cell / Q000150:complications* / Q000175:diagnosis; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged