PA patients with AVS-confirmed lateralisation to the left adrenal and signed study consent will be included in this study group. EUS will be performed. If EUS identifies an adrenal nodule in the left adrenal, EUS-guided fine needle tissue sampling of the adenoma will be performed, before a subsequent EUS-RFA treatment procedure will be performed. Follow-up after 2 weeks, 3 months and 12 months for evaluation of clinical and biochemical outcome, and procedural complications.

Patients will fast, receive prophylactic antibiotics and conscious sedation prior to the endoscopic procedure.The procedure is performed with a standard linear echo-endoscope with a 3.7 mm or larger working channel. The left adrenal is identified from the fundus of the stomach. Color-Doppler is used to map adrenal vascularity. Ultrasound contrast is used to demarcate the border of the tumour. EUS-guided fine needle tissue sampling from tumour tissue is performed. The RFA ablation catheter is water-cooled and stable temperature is maintained at 70-75 degrees celsius until formation of heat bubbles can be seen on EUS. If necessary, the procedure is repeated after moving the probe until the whole adenoma volume is ablated. Ultrasound contrast medium is used after the procedure to ensure that the target for the ablation is non vascularized, before termination. The patients will be observed at the postoperative unit a few hours, and further in the ward for 24h

EUS-RFA of left adrenal tumour in PA with AVS-verified left lateralisation

PA patients with suspicion of aldosterone overproduction in their left adrenal, but without fulfilling the strict AVS lateralization criteria, either due to a non-representative AVS, or a representative AVS but without significant left-sided lateralization (LI \< 4), and where the study investigators consider EUS-RFA treatment as an aldosterone-reducing procedure to be of high potential clinical and biochemical benefit for the patient, will be included in this study group after signed consent. EUS will be performed. If EUS identifies an adrenal nodule in the left adrenal, an EUS-guided fine needle tissue sampling of the adenoma will be performed, before a subsequent EUS-RFA treatment procedure. Follow-up after 2 weeks, 3 months and 12 months for evaluation of clinical and biochemical outcome, and procedural complications.

EUS-RFA of left adrenal tumour in PA, "debulking group"

MACS patients with AVS-confirmed lateralisation the left adrenal gland and CT showing left-sided tumour will be included in this study group after signed consent. EUS will be performed, and a EUS-guided fine needle tissue sampling of the adenoma will be performed, before a subsequent EUS-RFA treatment procedure. Follow-up after 2 weeks, 3 months and 12 months for evaluation of clinical and biochemical outcome, and procedural complications.

EUS-RFA of left adrenal tumour in MACS with AVS-verified left lateralisation

MACS patients with AVS-confirmed bilateral cortisol overproduction and bilateral tumours will be included in this study group after signed study consent. EUS will be performed, and EUS-guided fine needle tissue sampling of the adenoma will be performed, before a subsequent EUS-RFA treatment procedure. Follow-up after 2 weeks, 3 months and 12 months for evaluation of clinical and biochemical outcome, and procedural complications.