Acta clinica Croatica, Vol. 39 No. 2, 2000.
Original scientific paper
Ectopic ACTH Secretion and Cushing’s syndrome
Milan Vrkljan
B. Vizner
A. Zawawi
M. Bekić
M. Gorečan
I. Grbac
Abstract
Ectopic ACTH secretion was the first paraneoplastic endocrine syndrome described in the literature. The most common tumors associated with ectopic ACTH production are small-cell lung cancer and atypical carcinoids. High cortisol levels have also been described in patients with adenocarcinoma and large-cell carcinoma of the lung, other carcinoid tumors, thymoma, neural crest tumors, medullary carcinoma of the thyroid, and bronchial adenomas. Patients rarely live long enough for frank Cushing’s syndrome to develop. A 30-year-old male is described, who was admitted to endocrinology ward for clinical features of Cushing’s syndrome. Outpatient examination showed high levels of plasma cortisol on several occasions, without suppression of night dexamethasone test. Laboratory tests performed during his hospital stay showed an increased level of serum cortisol without suppression of night dexamethasone test, increased level of ACTH, and decreased testosterone level, increased 17 OHCS in urine. CT scan of adrenal and pituitary glands, and chest x-ray were normal. The patient was discharged with an appointment made for surgical exploration of the pituitary gland. Transnasal selective partial hypophysectomy was performed, however, excisional biopsy showed no microadenoma while the symptoms persisted postoperatively. The patient received TCT hypophysis in a maximal dose, and elevated ACTH level was found to persist after 37 days of treatment. One year later, the patient was readmitted for persistent cushinoid appearance. After complete investigations for ectopic ACTH secreting tumor, chest x-ray showed an infraclavicular, circular, sharply demarcated inhomogeneous lesion of the left lung, 2x3 cm in size. Three months later, lobectomy was performed and pathohistologic examination pointed to a carcinoid (argentaffinoma). During hospitalization, the symptoms of Cushing’s syndrome regressed. In conclusion, CRH test which usually distinguishes between hyperadrenocorticism associated with ectopic ACTH secretion and hypersecreting adrenal tumors is sometimes misleading because of the large overlap in normal and abnormal responses. In this case, chest or abdominal CT scan or MRI should be performed, because these are the most common sites of ectopic ACTH secreting tumors.
Keywords
ACTH syndrome - ectopic; Corticotropin - secretion; Cushing’s syndrome - pathology
Hrčak ID:
14952
URI
Publication date:
1.6.2000.
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