Background: The most typical presentation of Cushing’s syndrome includes truncal obesity, purple skin striae, moon face, emotional and sleep disturbances, plethora and proximal muscle weakness. ACTH-independent
micronodular adrenocortical hyperplasia (AIMAH) is a rare cause of Cushing’s syndrome with male predominance. We describe here a female patient with atypical Cushing’s syndrome due to AIMAH presenting as a severe
myopathy with diaphragm atrophy.
Case report: A 56-year-old female suffered from hypertension, NIDDM, central adiposity and muscle weakness for 5 years, but her appearance was not typically cushingoid. She was admitted to hospital because of respiratory
insufficiency due to diaphragm atrophy. Reconstructive surgery of the diaphragm was performed, but without any significant improvement. Six months later, she was referred to us with suspicion of Cushing’s syndrome.
Her ACTH levels in plasma samples collected throughout the day were below normal. The cortisol level was at upper limit of the normal range. The plasma circadian cortisol profile was blunted and 1 mg dexamethasone did not induce any inhibition of serum cortisol. The subsequent administration of 8 mg of dexamethasone did not cause any further suppression of cortisol. While these findings were consistent with a diagnosis of adrenocortical
adenoma, computed tomography demonstrated slightly enlarged, contrast-enhanced adrenals (both adrenal glands).
Results: ACTH-independent Cushing’s syndrome was diagnosed and the patient underwent bilateral adrenalectomy. Histological studies revealed bilateral micronodular adrenal hyperplasia. Soon after the surgery the woman
became hypoadrenal and received replacement therapy. Hypertension, NIDDM, myopathy and respiratory comfort improved.
Conclusions: Hypercortisolemia may infrequently present as atypical clinical syndrome. Patients with unclear muscle atrophy, especially accompanied by NIDDM and hypertension should by screened for Cushing’s syndrome.

Keywords: adrenal hyperplasia, Cushing’s syndrome, diaphragm atrophy