Adrenal tumours in patients with pathogenic APC mutations: a retrospective study

Adrenal tumours are associated with familial adenomatous polyposis (FAP). In the literature, most studies use the clinical definition of FAP (more than 100 adenomatous polyps found in endoscopic studies). However, not all patients that meet clinical criteria for FAP carry pathogenic mutations in the adenomatous polyposis coli (APC) gene, as there is genetic heterogeneity responsible for FAP with the polyposis sometimes explained by genetic and environmental factors other than pathogenic APC mutations. Reciprocally, not all the patients with pathogenic APC variants will fulfil the classic criteria of FAP.

This study aims to investigate the characteristics of adrenal tumours in patients with pathogenic or likely pathogenic APC variants and explore the hormonal function of these patients.

This is a retrospective cohort study. Patients with pathogenic or likely pathogenic APC variants were recruited and their radiological assessments were reviewed. Patient demographic data, APC variants, adrenal mass characteristics and hormonal testing results were collected.

The prevalence of adrenal mass was 26.7% (24/90) among patients with pathogenic or likely pathogenic APC variants. Using the classic definition, the prevalence was 32.4% (22/68). Four patients had adrenal hormone testing, two of which had Conn's syndrome and two had nonspecific subclinical results.

In our cohort, the prevalence of adrenal tumours among patients with pathogenic and likely pathogenic APC mutations is at least twice to three times higher than the general population prevalence reported from international population-based studies. The hormonal functions of patients with pathogenic APC variants and adrenal tumours can be investigated with routine testing in further research.