Adrenal Vein Sampling as a Tool to Identify Biomarkers That Aid the Diagnosis of Adrenocortical Carcinoma

Inclusion Criteria: In order to be eligible to participate in the study group, a subject must meet all of the following criteria: * Patient age ≥18 years * High clinical suspicion of adrenocortical carcinoma, based on clinical signs (due to hormonal overproduction), steroid hormone profile and radiological features (e.g. tumor size ≥4cm, inhomogenous aspect and tumor attenuation of HU ≥10) * Able to provide signed informed consent In order to be eligible to participate in the control group, a subject must meet all of the following criteria: * Patient age ≥18 years * Routine diagnostic process includes AVS * No suspicion of malignancy * Able to provide signed informed consent Exclusion Criteria: Patients are not able to participate if: * They have a known allergy to (iodinated) contrast fluid * They use vitamin K antagonizing anticoagulants or DOAC's, except for when on the day of the adrenal vein sampling the anticoagulants are already stopped for the following adrenal surgery, and in case of using vitamin K antagonizing anticoagulants the INR is \<3 * The platelet count is below 20 * Anatomy of the adrenal vein is not suitable for performing the AVS procedure, based on the judgement of an experienced interventional radiologist * Contraindications for use of Synacthen * They have a known hypersensitivity to any of the substances of Synacthen * They are pregnant