A 34-year-old Chinese woman presenting with general fatigue was found to have central hypothyroidism and low-normal insulin-like growth factor 1 (IGF-1). Although she had no cushingoid features, her adrenocorticotropic hormone levels were suppressed, while her serum cortisol levels were normal. Cortisol secretion was not suppressed following a 1-mg dexamethasone suppression test, and computed tomography revealed a left adrenal tumor. After adrenalectomy, her thyroid function, growth hormone (GH) secretion, and IGF-1 levels were normalized. A histopathological examination confirmed adrenocortical adenoma. This case demonstrates that mild autonomous cortisol secretion can impair GH secretion and cause central hypothyroidism even in the absence of any overt cushingoid features.
Katahira et al. (Thu,) studied this question.