Endocrine Abstracts

Ectopic ACTH secretion due to malignant tumor is the most frequently underdiagnosed form of Cushing`s syndrome .

A 41-year old woman was admitted to our Center with severe hypertension, oedema, oligomenorrhea which developed 5 months ago. The purpose of admittion was to exclude the endocrine genesis of the clinical features. There were no biochemical alterations. Suprisingly, high levels of urinary cortisol (>8000nmol/l) and plasma ACTH (morning 136 ng/ml, evening 174 ng/ml) were revealed.

MRI of the pituitary gland was normal, however adrenal MRI revealed leftside adrenocortical hyperplasia. She demostrated abnormal feedback control, with lack of response to desmopressine, so the source of ACTH seemed to be ectopic. CT of the chest localized the lung tumor, CT of abdomen demonstrated a tumor of lien. The results of selective venous sampling for ACTH ruled out ACTH hypersecretion from lien tumor.

She was operated on the lung and surgery cured the hypercorticolism in the patient and she developed adrenal defficiency postoperatively. In the remove tumor histological heterogenety was seen three distinct populations of cells: small, oats, solid, were identified. The tumor stained strongly positive for ACTH on immunocytochemical studies and only oats cells confirmed excessive ACTH production in vitro. Histology showed focuses of necrosis, haemorrahage, inflammation, this pointed to tuberculosis.

We consider the patient had an unusual syndrome of ectopic ACTH secretion due to combined malignant lung tumors, that show non-typical stigmata of Cushing`s syndrome.