Background: Pediatric Cushings syndrome is a rare condition and its diagnosis is always a challenge to the clinicians. The hypercortisolism can be classified as ACTH-dependent (Cushings disease) and ACTH-independent. The latter group comprises several hereditary conditions. One of them is primary pigmented nodular adrenocortical disease (PPNAD) which occurs isolated or as part of Carney complex (CNC). It is known that adult patients with Cushings syndrome due PPNAD exhibited a paradoxical increase of urinary cortisol excretion in response to dexamethasone. However, this finding has been rarely described in children.
Case report: Two 14-year-old twin girls belonging to a large Azorean family with CNC have been followed in our outpatient consultation since the age of 4-years. Her mother died at age of 28-years due to adrenal carcinoma arising in the context of PPNAD. The children and her mother were heterozygous for the mutation S147G in the gene of PRKAR1A. Since early childhood, they present strong spotty skin pigmentation. At 13-year-old, one of the twins started complaining of olygomenorrhea and later on to amenorrhea. She gained 6 kg in <1 year. Her blood pressure was raised to 140/90 mmHg. The circadian cortisol variation was abolished and ACTH was below the lower limit of the assay. Oral administration of dexamethasone, 0.5 mg each 6 h for 48 h, produced a paradoxical increase in urinary cortisol excretion (100% over basal value). These findings were not found in the other twin. She was submitted to adrenalectomy and the histologic examination confirmed the diagnosis of PPNAD.
Conclusion: As in most adults with Cushings syndrome due to PPNAD, a paradoxical increase in urinary cortisol excretion in response to dexamethasone is also found in children. When this increase is over 100% it is pathognomonic of PPNAD.
20 - 22 Sep 2014
European Society for Paediatric Endocrinology