Cushing's syndrome and early growth hormone hypersecretion in a child with Carney complex: a case report

Carney complex (CNC) is a rare autosomal dominant syndrome characterized by multiple endocrine and non-endocrine tumors. In childhood, Cushing's syndrome due to primary pigmented nodular adrenocortical disease (PPNAD) may occur, while growth hormone (GH) hypersecretion before puberty is exceptionally rare.

A 5-year-old girl presented with rapid weight gain, facial changes, hypertension, hypokalemic alkalosis, and kidney stones. Biochemical evaluation confirmed ACTH-independent Cushing's syndrome, and abdominal magnetic resonance imaging (MRI) revealed bilateral adrenal nodules consistent with PPNAD. Family history of endocrine tumors and cardiac myxomas suggested CNC, subsequently confirmed by genetic testing showing a mutation of the PRKAR1A gene in both the patient and her father. Bilateral adrenalectomy resolved hypercortisolism. At 8.6 years, the patient showed an accelerated growth velocity (+2.48 SDS) with elevated IGF-1 levels and lack of GH suppression during an oral glucose tolerance testing, despite a normal pituitary MRI. She remained asymptomatic apart from growth acceleration, which was carefully monitored during follow-up. Over 18 months accelerated growth persisted with pubertal progression, but IGF-1 levels eventually normalized and brain MRI remained stable; therefore, treatment for GH excess was deferred.

This case highlights the importance of considering CNC in pediatric ACTH-independent Cushing's syndrome and underlines the role of genetic testing. It also demonstrates that GH hypersecretion may emerge earlier than current screening recommendations, underscoring the need for surveillance starting at the onset of puberty.