A Rare Case of PRKACA Duplication-Associated Childhood-Onset Primary Pigmented Nodular Adrenocortical Disease

Abstract

Primary pigmented nodular adrenocortical disease (PPNAD) is a rare but important cause of adrenocorticotropic hormone (ACTH)-independent Cushing syndrome (CS). It usually presents as cyclical CS in young adults. Childhood onset of PPNAD is exceedingly rare. About 90% of cases of PPNAD are associated with Carney complex (CNC). Both PPNAD and CNC are linked to diverse pathogenic variants of the PRKAR1A gene, which encodes the regulatory subunit type 1 alpha of protein kinase A (PKA). Pathogenic variants of PRKACA gene, which encodes the catalytic subunit alpha of PKA, are extremely rare in PPNAD. We report a case of a female child, aged 8 years and 3 months, who presented with features suggestive of CS, including obesity, short stature, hypertension, moon facies, acne, and facial plethora but without classical striae or signs of CNC. Hormonal evaluation confirmed ACTH-independent CS. However, abdominal imaging revealed normal adrenal morphology. Genetic analysis identified a duplication of the PRKACA gene on chromosome 19p, which is linked to PPNAD. The patient underwent bilateral laparoscopic adrenalectomy, and histopathological study confirmed the PPNAD diagnosis. Postoperative follow-up showed resolution of cushingoid features and hypertension. To our knowledge, this is the first reported case of a female child with PRKACA duplication presenting as CS due to PPNAD.

Keywords: Carney complex; Cushing syndrome; PPNAD; PRKACA.

Figure 1.

Growth chart by the Indian Academy of Pediatrics [9] illustrating the patient's progression. At baseline, the patient's height was 114.5 cm, placing her below the 3rd percentile for her age, while her weight was 37 kg, corresponding to the 75th to 90th percentile range. Five months after bilateral adrenalectomy, she exhibited a 9-cm increase in height and a 10-kg reduction in weight.

Figure 2.

A and B, clinical signs of Cushing syndrome observed during physical examination: moon facies, dorsocervical fat pad, generalized obesity, short stature, and facial acne. C, Follow-up photograph taken 5 months after bilateral adrenalectomy, showing a reduction in weight, resolution of facial acne and acanthosis, and an increase in height.

Figure 3.

Adrenal computed tomography (CT) showing normal adrenals bilaterally (white arrows).

Figure 4.

A, Gross image of the excised adrenal glands B, Histopathological findings of adrenal tissue stained with hematoxylin and eosin (H&E) stain, showing nonencapsulated micronodules (green arrows) with internodular cortical atrophy. C, Magnified image of a single cortical nodule showing an unencapsulated nodule composed of large polygonal lipid-poor cells with abundant eosinophilic granular cytoplasm with lipofuscin granules. Nuclei show prominent nucleoli. Peri-nodular cortex shows compression atrophy (H&E stain, 400X).