Lack of mutations in the gene coding for the hGR (NR3C1) in a pediatric patient with ACTH-secreting pituitary adenoma, absence of stigmata of Cushing's syndrome and unusual histologic features.

BACKGROUND

Rare cases of human glucocorticoid receptor (hGRalpha) (NR3C1) gene mutations have been described in the gemline or somatic state in Cushing's disease (CD).

AIM

We describe a pediatric patient with CD with clinical evidence of partial glucocorticoid resistance (GR) due to the relative absence of stigmata of Cushing's syndrome (CS).

CASE DESCRIPTION

A 14-year-old boy with slow growth and hypertension, but no other signs of CS was admitted for CD evaluation. Urinary free cortisol levels (UFC) were consistently 2-3-fold the upper normal range. Pituitary magnetic resonance imaging (MRI) revealed a 3x4 mm hypoenhancing lesion in the right side of the pituitary gland anteriorly (microadenoma). A graded dexamethasone suppression test indicated that the patient had partial GR. Histology confirmed an adrenocorticotrophin (ACTH)-producing pituitary adenoma. We hypothesized that a NR3C1 mutation was present. Sequencing of the entire coding region of the gene produced normal results in both peripheral and tumor DNA.

CONCLUSION

We present the case of a pediatric patient with an ACTH-producing tumor but little evidence of CS. No mutations in the coding sequence of NR3C1 were detected. We conclude that low level somatic mosaicism for NR3C1 mutations or a mutation in another molecule participating in hGRalpha-signaling may account for this case.