Primary pigmented nodular adrenal dysplasia (PPNAD) is a rare benign adrenal condition characterised by ACTH-independent autonomous hypersecretion of cortisol, leading to Cushing syndrome.
PPNAD is inherited as an autosomal dominant trait, which has yet to be confidently mapped. Patients are usually children or young adults with a female predilection 1.
Presentation is usually with Cushing syndrome, which is often relatively mild, on account of cortisol levels being only mildly elevated, and thus often not recognised from many years 1.
PPNAD is associated with Carney complex, which is sometimes the reason for diagnosis.
The glands are not significantly enlarged, but contain multiple bilateral nodules, typically 2-5 mm in diameter, although in older patients they may be as large as 1-2 cm 1. The intervening 'normal' gland appears atrophic.
The nodules range in density from isodense to the rest of the adrenal gland, to somewhat hyperdense.
- lower signal intensity than surrounding atrophic adrenal tissue
- signal drop out demonstrated on out-of-phase imaging
- T2: lower signal intensity than surrounding atrophic adrenal tissue
Treatment and prognosis
The treatment of choice is bilateral adrenalectomy. As the trait is autosomal dominant, but does not yet have a gene test, screening of family members biochemically is recommended to ensure normal cortisol levels.