Endocrine Abstracts

ACTH-independent micronodular adrenocortical hyperplasia is a rare cause of Cushing syndrome. In some forms of micronodular adrenal disease, darkly pigmented micronodules are seen in the presence of atrophy of the peripheral adrenal tissue. In most cases of pigmented micronodular hyperplasia Carney complex is associated with the disease. Here, we present a case of Cushing syndrome due to sporadic primary pigmented micronodular hyperplasia not accompanied by Carney complex.

A 30-years old female patient was admitted to hospital because of weight gain, swelling of the face, hypertension and muscle weakness. Physical examination revealed classic Cushingoid features. Her basal serum and urinary free cortisol levels were elevated and ACTH levels were supressed. After overnight (1 mg), low dose (2 mg) and high dose (8 mg) dexametasone tests urinary and serum cortisol levels were not supressed and even elevated further. On abdominal MRI, micronodular hyperplasia was shown on both adrenal glands. A 2 mm. lesion suggesting microadenoma was also shown on the MRI of the pituitary. Than a petrosal sinus sampling was performed. In the samples obtained from petrosal sinus and periphery, ACTH levels were all supressed and did not increase after CRH stimulation. GIP-dependent Cushing was excluded by studying cortisol response to glucose loading. No physical or laboratory finding regarding Carney complex could be demonstrated. Cushing syndrome was concluded to be due to bilateral surrenal hyperplasia and a bilateral adrenalectomy was performed. In pathological examination, multiple, gray-brown colored micronodules, 0.5–1.2 mm. in diameter were detected in both adrenals. After the operation, she was administered steroid replacement therapy and her Cushingoid features regressed progressively during follow up.

Primary pigmented nodular hyperplasia is a rare diagnosis which should also be considered in patients with ACTH- independent bilateral adrenal disease not exhibiting features of Carney complex.