Adrenal Incidentalomas During Diagnostic Work-up of Colorectal Cancer Patients: What is the Risk of Metastases?

Adrenal incidentalomas (AIs) are regularly discovered on staging computed tomography (CT) of patients with colorectal cancer (CRC). Although CRC is considered unlikely to metastasize to the adrenal gland, it is not known how often an AI appears to be a CRC metastasis. This causes a diagnostic dilemma for many patients with newly diagnosed CRC. This study aimed primarily to describe the incidence of AIs and adrenal metastases in CRC patients. A single-center cohort of 475 consecutive patients with newly diagnosed CRC was defined. Retrospectively, all radiology reports and multidisciplinary team meeting reports were assessed for the presence of adrenal abnormalities. All AIs shown on staging CT were reevaluated for the purpose of this study, and the sizes of these adrenal glands were determined. Based on the CT reevaluation, follow-up imaging, and clinical follow-up assessment, conclusions on the presence or absence of adrenal metastases were drawn. The incidence of AIs in this CRC patient cohort was 10.5% (50/475). In 96% (48/50) of the patients with AIs, adrenal metastases could be ruled out. No solitary adrenal metastases were encountered. In two patients who had widespread systemic disease without curative treatment options, the AIs were considered to be adrenal metastases (cohort incidence, 0.4%). This is the first study to report on adrenal incidentalomas in CRC patients. In newly diagnosed CRC patients without disseminated disease, AIs can be considered benign, and no additional imaging is indicated to rule out adrenal metastases in this group.