Bilateral Adrenal Incidentalomas: A Case Report and Review of Diagnostic Challenges
OBJECTIVE The development and progression of sporadic adrenocortical tumours are poorly understood. In autopsy studies adrenocortical tumours are found in between 2 and 9% of the general population. In congenital adrenal hyperplasia (CAH), decreased production of cortisol leads to increased secretion of ACTH from the pituitary, resulting in hyperplasia of the adrenals. More than 95% of all cases of CAH are due to steroid 21-hydroxylase deficiency, resulting from mutations in the CYP21 gene. In subjects homozygous and heterozygous for CYP21 mutations, adrenocortical tumours have been found in a high frequency compared to the general population, suggesting that chronic ACTH stimulation may play a role in the development of this tumour form. In order to test whether mild undiagnosed CAH is a common predisposing factor, we screened 27 patients with sporadic adrenocortical tumours for CYP21 mutations. DESIGN A retrospective study. PATIENTS We screened 27 patients with sporadic adrenocortical tumours, representing both benign and malignant as well as hormonally active and silent lesions. MEASUREMENTS Mutation analyses of the CYP21 gene was performed by allele-specific PCR on high molecular weight DNA. The method used detects the nine CYP21 mutations that are responsible for 95% of all disease-causing alleles in CAH. RESULTS No mutations were detected in any of the 23 DNA samples that were prepared from leucocytes. In 4 cases where no leucocyte DNA was available, tumour tissue was analysed. In one of these tumours, two CYP21 mutations, V281 L and L307insT, were found in heterozygous form. CONCLUSION Our data indicate that mild undiagnosed congenital adrenal hyperplasia is not a common underlying factor predisposing to adrenocortical tumours, at least not in the Swedish population.