Small-Cell Lung Cancer Presenting as Diabetes Insipidus and Cushing's Syndrome

Abstract

Small-cell lung cancer presenting with a combination of cranial diabetes insipidus and Cushing's syndrome secondary to ectopic adrenocorticotropin (ACTH) secretion is very rare and has only been described previously in one case report Our patient was a 49 year old man, in whom the initial presenting features of small-cell lung cancer were cranial diabetes insipidus secondary to pituitary metastases and severe hypokalaemia resulting from ectopic ACTH hormone secretion. This case is a remarkable example of the complex metabolic endocrine manifestations of small-cell lung cancer.

Nephrogenic diabetes insipidus as the first manifestation of Ectopic ACTH syndrome in a HIV infected patient

“…Most of the previous reports of the association between EAS and DI were related to the presence of pituitary metastases causing central DI [4], and only one report described a mixed central and nephrogenic DI [5]. Thus, to our knowledge, this is the first description of purely NDI caused by EAS.…”

“…Very few cases of DI have been reported in association with EAS, and most of them were linked to intrasellar metastasis of the primary ACTH -producing tumor [4]. In this case, diluted polyuria persisted after vasopressin administration and pituitary image did not show infiltrative lesions, indicating a nephrogenic form of DI, which is a frequently unknown or forgotten manifestation of severe hypercortisolism.…”

“…Ectopic ACTH secretion is a rare manifestation of lung tumors, occurring in 3.2% to 4.5% of cases [4]. It often results in severe hypercortisolemia, which increases the already high morbimortality of the underlying condition.…”

“…The clinical presentation is heterogeneous and appears to be related to the degree of hypercortisolism, varying from typical CS symptoms and signs (such as central obesity, moon-like face and violaceous striae) to an unusual or atypical picture with aldosterone-like effects, psychiatric manifestations, weight loss, polyuria, skin pigmentation, ankle edema, osteoporosis, aortic dissection and infections [1,2,[4][5][6][7].…”

“…Tumors manifested by EAS have been associated with reduced survival despite appropriate treatment, possibly due to complications such as sepsis, aortic dissection and gastrointestinal haemorrhage [4,20]. Although the ideal treatment is excision of the tumor, drugs that help to control the effects of hypercortisolemia are important tools to reduce some of these complications.…”