Corticotroph adenoma of the pituitary in a patient with X-linked adrenal hypoplasia congenita due to a novel mutation of the DAX-1 gene.

OBJECTIVE Mutations in the DAX-1 gene result in X-linked congenital adrenal hypoplasia. The classic clinical presentation is primary adrenal insufficiency in early life and hypogonadotropic hypogonadism at the time of expected puberty, but recent data have expanded the phenotypic spectrum of DAX-1 mutations. We report the occurrence of an ACTH-secreting adenoma in a patient with X-linked congenital adrenal hypoplasia. DESIGN AND METHODS Detailed clinical, radiological and pathological investigation of the pituitary adenoma. Genomic analysis of the DAX-1 gene in the patient and his mother. RESULTS In this patient, primary adrenal failure had been diagnosed at 3 years of age and, despite replacement therapy, at 30 years of age progressive pigmentation developed and impairment of the visual field followed. ACTH was 24 980 pg/ml and nuclear magnetic resonance disclosed a huge pituitary adenoma. Three transsphenoidal operations and radiotherapy were necessary to remove the tumor mass and control ACTH secretion. Histologically, the adenoma was composed of chromophobic and basophilic neoplastic cells with positive immunostaining for ACTH. Moreover, a novel mutation was found both in the patient and his mother: a 4 bp insertion (AGCG) at nucleotide 259, in exon 1 resulting in a frame shift and premature termination. CONCLUSIONS This case suggests that in adrenal hypoplasia congenita the development of a pituitary adenoma should be considered when a sudden rise of ACTH occurs despite adequate steroid substitution.