[Primary pigmented nodular adrenocortical dysplasia. A rare cause of Cushing's syndrome].

HISTORY AND CLINICAL FINDINGS

A 29-year-old woman was found to have arterial hypertension (175/115 mm Hg). The 24-hour profile showed no diurnal cortisol variations with normal concentrations and 24-hour urinary cortisol was normal. 14 months later there was definite hypercortisolism with discrete Cushing signs and no amenorrhoea. She also had signs of depression.

INVESTIGATIONS

Routine laboratory tests were unremarkable. ACTH and dehydroepiandrosterone levels were reduced and there was marked hypercortisolism (600 micrograms/24h). Bone densitometry showed osteoporosis. The low- and high-dose dexamethasone inhibition tests showed no suppression of 24-hour urinary cortisol, raising the suspicion of adrenal cortical adenoma or carcinoma. Magnetic resonance imaging (MRI) of both adrenals was normal, and scintigraphy showed physiological storage. MRI of the skull was normal.

TREATMENT AND COURSE

As ACTH-independent hypercortisolism had been proven, unilateral adrenalectomy was performed. The specimen showed primary pigmented nodular adrenocortical dysplasia (PPNAD). While cortisol levels and blood pressure were at first normal, hypercortisolism had recurred 5 months postoperatively. The other adrenal was removed and showed a similar histology. A malignant melanoma of the shoulder was also found, perhaps part of a Carney syndrome.

CONCLUSION

PPNAD should be included in the differential diagnosis of an ACTH-independent Cushing's syndrome with normal adrenal on imaging, perhaps as part of a Carney syndrome.