35426842

Imaging Aldosterone-Producing Adrenocortical Carcinoma With 68 Ga-Pentixafor PET/CT

QiaoQiao Shu, MD, Maoxue Deng, MD, Yue Chen, MD, Nan Liu, MD, and Liang Cai, MD

Abstract: Chemokine receptor 4 (CXCR4) is a 7-transmembrane G protein-coupled receptor, and pentixafor is considered to be a potent ligand for the CXCR4 receptor. Recently, 68Ga-pentixafor has been reported as a potential PET imaging agent for CXCR4-positive tumors and inflammatory lesions, including adrenocortical lesions. We report a case of primary aldo- steronism due to adrenocortical carcinoma with intense 68Ga-pentixafor ac- tivity on PET/CT.

Key Words: 68Ga-pentixafor PET/CT, CXCR4, adrenocortical carcinoma, primary aldosteronism

(Clin Nucl Med 2022;47: e572-e573)

Received for publication January 11, 2022; revision accepted February 19, 2022. From the Department of Nuclear Medicine, The Affiliated Hospital of Southwest Medical University; Nuclear Medicine and Molecular Imaging Key Labora- tory of Sichuan Province; and Academician (Expert) Workstation of Sichuan Province, Luzhou, Sichuan, China.

Conflicts of interest and sources of funding: none declared.

Correspondence to: Liang Cai, MD, Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, No 25 TaiPing St, Jiangyang District, Luzhou, Sichuan, 646000, China. E-mail: cllc131420@sina.com.

Copyright @ 2022 Wolters Kluwer Health, Inc. All rights reserved. ISSN: 0363-9762/22/4708-0572

DOI: 10.1097/RLU.0000000000004202

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FIGURE 1. The patient, a 42-year-old man with 7+ years of hypertension, was admitted to the hospital with blurred vision, dizziness, and chest tightness without obvious inducement. On admission, blood potassium level was measured at 2.75 mmol/L, sodium level at 148.3 mmol/L, aldosterone level at 83.30 ng/dL, and aldosterone renin ratio at 23.73. The 24-hour urine catecholamine measurements showed no significant abnormalities, and the highest blood pressure was measured at 180/110 mm Hg. Based on laboratory results, primary aldosteronism was suspected. The adrenal-enhanced CT showed an irregular soft tissue mass (curved arrow) in the left adrenal region, measuring approximately 9.7 x 7.9 x 5.5 cm, with nodular uneven enhancement in the arterial phase (A), increasing enhancement in the venous phases (B) and delayed phases (C), and progressive enhancement overall. For further examination, the patient was then recruited to our 68Ga-pentixafor PET/CT trial, approved by the internal research board of our institution. The MIP image (D) and axial views (E, PET image; F, CT scan; G, PET/CT fused image) showed an irregular soft tissue mass in the left adrenal gland with increased CXCR4 expression (solid arrow; SUVmax, 9.8). Then the patient underwent laparoscopic left adrenal tumor resection under general anesthesia. Postoperative pathological examination: the Weiss score was 7, supporting adrenal cortical carcinoma. The hypertension and hypokalemia resolved after surgical removal of the tumor, hence the clinical diagnosis of primary hyperaldosteronism caused by adrenocortical carcinoma. Adrenocortical carcinoma is a very rare and highly malignant tumor originating from the adrenal cortex with a poor prognosis and an estimated incidence of 0.5 to 2 new cases per million people per year. 1,2 The most common clinical manifestation of adrenocortical carcinoma is Cushing syndrome, with rare symptoms of isolated aldosteronism, such as hypertension and hypokalemia.3,4 Aldosterone-secreting adrenocortical carcinoma needs to be differentiated from pheochromocytoma. Pheochromocytoma and aldosterone-producing adrenocortical carcinoma have similarities; for example, they are both associated with hypertension.3 CXCR4 is expressed by a variety of inflammatory and malignant cells.6 Therefore, in vivo quantification of CXCR4 expression using CXCR4-targeted PET/CT imaging has received some consideration.7-9 Recently, a growing literature has reported that 68Ga-pentixafor PET/CT plays an important role in the diagnosis of some tumors and inflammation.10-12 It has now been demonstrated that the high expression of CXCR4 in aldosterone-producing adrenal tumors is closely associated with the expression of CYP11B2 (aldosterone synthase).13 It has also been reported that adrenocortical cancer is known to have intense 68Ga-pentixafor activity.14 Our case shows that primary aldosteronism due to adrenocortical carcinoma has intense 68Ga-pentixafor activity on PET/CT, which may provide valuable diagnostic information for adrenocortical carcinoma and possibly even guide CXCR4-mediated nuclide therapy.

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