Endocrine Abstracts

Introduction: Familial Adenomatous Polyposis (FAP) is an autosomal dominant disease classically characterized by the development of hundreds or thousands of adenomas in the rectum and colon during the second decade of life. Almost all patients will develop colorectal cancer (CRC) if not identified and treated at an early stage. It is a multisystem growth disorder so there is an increased risk of developing extraintestinal manifestations. In this context, an increase in adrenal pathology compared to the general population has been described. We aimed to report the frequency, functional characteristics and progressions of adrenal lesions in FAP patients.

Materials and Methods: Prospective study, selecting 17 living patients diagnosed and registered with APC mutations under follow-up from the Digestive Department of the Hospital Universitario de Navarra (HUN) with current or past follow-up in the Endocrinology Department. Radiological tests, clinical, and analytical variables were analyzed.

Results: The study population included 12 men (64.7%) and 5 women (35.3%), with a mean age of 47 years. The median age at diagnosis of FAP was 28 years, with a mean follow-up time of 16 years. All patients had an abdominal imaging study (CT or MRI), detecting lesions in 5/17 (31.25%). All were incidental findings presented as non-functioning adenomas in the analytical tests performed. The study consisted of the overnight 1mg dexamethasone suppression test, catecholamine/metanephrine determination, adrenal androgen production, and if appropriate, screening of primary hyperaldosteronism. None showed significant growth during follow-up (defined as changes in the size of ≥2 mm were considered clinically significant). No major endocrinological alterations (defined as nodular disease or thyroid carcinoma, thyroid autoimmunity, diabetes, obesity) were detected when comparing both groups. There were also no differences in gender, age or time since diagnosis.

Conclusion: Adrenal lesions are common in patients with FAP who undergo abdominal imaging. They appear to follow a benign and slowly progressive course, presenting clinically and analytically as non-functioning lesions.