FRI146 Stereotactic Ablative Radiotherapy As A Local Valuable Therapeutic Procedure To Control Aldosterone-Secreting Adrenocortical Carcinoma

Disclosure: L.M. Mermejo: None. R.H. Zanella: None. L. Cocicov: None. C.A. Molina: None. S. Tucci Jr: None. J. Elias Jr: None. V.F. Muglia: None. G. Viani: None. P.C. Elias: None. A.C. Moreira: None. M. De Castro: None. Aldosterone-secreting adrenocortical carcinomas (ACC) are rare and usually described as large tumors. We report the case of a 44-year-old man referred to our University Hospital presenting back pain, muscular weakness and hypokalemia. A year earlier, hypertension had been diagnosed triggered by the investigation of daily headaches. Throughout this period, hypertension had been refractory to antihypertensives and patient also showed progressive weight loss of 10 kg. At the time of presentation, the patient had no signs of cortisol or androgen excess, his blood pressure was 180x120 mmHg, and there was no peripheral edema or abdominal mass detected. Due to abdominal pain and liver enzymes abnormalities, an abdominal CT was performed and revealed a heterogeneously 10 x 8 x 6 cm (volume: 256 cm³) left adrenal mass compressing the left renal vein with invasion through the inferior cava vein and extending to the liver caudate lobe. He also had a sodium of 143 mmol/L, potassium of 1.2 mmol/L and metabolic alkalosis. The serum aldosterone level of 75 ng/dL and plasma direct renin concentration < 2 mIU/L whereas urinary fractionated metanephrines were within normal limits, suggesting a probable aldosterone-secreting ACC. His family history was negative for hypertension or adrenal diseases. The patient was initially treated with spironolactone and potassium replacement with clinical improvement and an open adrenalectomy was proposed. However, patient professed to be Jehovah's Witnesses and refused the surgery due to the risk of blood transfusions. Therefore, the patient received mitotane but owing to hepatotoxity, the drug was withdrawn after two months of follow-up. A follow up abdominal MRI after 10 months of diagnosis revealed an increase in the mass (12 x 8 x 9 cm; volume: 460 cm³) and, now, extending to the left kidney. A CT-guided percutaneous biopsy showed an ACC with a Weiss score of three and the immunohistochemistry was positive for vimentin, inhibin and MART-1/ Melan A. After a multidisciplinary discussion, it was proposed to use stereotactic ablative radiotherapy (SABR) as an alternative option. The patient accepted SABR, being treated with 35Gy/5 fractions. During the follow-up, the patients had a progressive improvement of pain complaints, reduction of tumor burden after eighteen months on control abdomen CT (9.1 x 4.9 x 8.7 cm; volume of 202 cm³), improvement of blood pressure and hypokalemia levels, reduction of antihypertensive drugs defined daily dose and potassium replacement as well as reduction of a serum aldosterone to 13 ng/dL and increased of paired renin to 25 mU/L. This is the first published report of a pure aldosterone-producing ACC patient receiving SABR. The response was significant, indicating that the use of SABR should be considered as an alternative for local treatment of aldosterone-secreting ACC when the surgery cannot be indicated. Presentation: Friday, June 16, 2023