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18F-FDG PET/CT Findings in a Patient With Primary Prostatic Synovial Sarcoma Combined With Adrenocortical Carcinoma

Zhenghao Tong, MD,* Xueqi Chen, MD,* Qian Li, MD,¡ Yan Fan, MD,* and Jianhua Zhang, MD*

Abstract: A 41-year-old man with 1-year history of hypertension was dis- covered to have a right adrenal mass on abdominal ultrasound. Contrast CT was performed to discriminate malignant from benign tumor, which re- vealed tumors of right adrenal gland and prostate. 18F-FDG PET/CT scan was performed for lesion characterization, and ruling out any distant metas- tasis. PET/CT scan showed high uptake in the right adrenal and prostatic le- sions, which were surgically approved as adrenocortical carcinoma and pri- mary prostatic synovial sarcoma.

Key Words: primary prostatic synovial sarcoma, 18F-FDG PET/CT, adrenocortical carcinoma

(Clin Nucl Med 2022;47: 723-724)

Received for publication December 13, 2021; revision accepted January 21, 2022.

From the *Department of Nuclear Medicine, Peking University First Hospital, Beijing, China; and ¡Department of Radiology, Massachusetts General Hos- pital, Harvard Medical School, Boston, MA.

Y.F. and J.Z. contributed equally to this case report.

Conflicts of interest and sources of funding: The research was supported in part by Beijing Science and Technology Project (Z181100001618017), Beijing TCM Science and Technology Foundation (JJ-2020-04), Interdisciplinary Clinical Research Project of Peking University First Hospital (2021CR32), and special fund for clinical research of Wu Jieping Medical Foundation (320.6750.2020-6-25). The authors declare that they have no conflicts of interest.

Correspondence to: Jianhua Zhang, MD, Department of Nuclear Medicine, Peking University First Hospital, No. 8, Xishiku St, West District, Beijing,

100034, China. E-mail: zjh@bjmu.edu.cn. Yan Fan, MD, Department of Nuclear Medicine, Peking University First Hospital, No. 8, Xishiku St, West District, Beijing, 100034, China. E-mail: fanyan@bjmu.edu.cn.

Copyright @ 2022 Wolters Kluwer Health, Inc. All rights reserved. ISSN: 0363-9762/22/4708-0723

DOI: 10.1097/RLU.0000000000004138

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FIGURE 1. A 41-year-old man with 1-year history of hypertension was referred to abdominal ultrasound to explore potential causes. In the right adrenal region, a 8.6 x 7.0 x 5.6-cm mass was revealed. Contrast CT was performed to discriminate malignant from benign tumor, and the suspected diagnosis of right adrenal gland mass was pheochromocytoma. A 5.9 x 6.3 x 3.9-cm mass of prostate was incidentally detected on CT and suspected for prostatic cancer, whereas the serum prostate-specific antigen was 0.1 ng/ml (normal 4 or less). 18F-FDG PET/CT scan was performed for lesion characterization and ruling out any distant metastasis. The lateral MIP (A) image showed increased 18F-FDG uptake in both right adrenal (short arrow) and prostatic regions (long arrow). Axial CT image showed enlarged prostate (B) with increased FDG uptake (SUVmax, 8.2) on corresponding PET (C) and fused PET/CT (D) (arrows). Axial CT image (E) revealed a tumor of right adrenal gland on CT with intense FDG uptake (SUVmax, 32.1) on the corresponding PET (F) and fused PET/CT (G) images (arrows). The patient received radical cystoprostatectomy, Bricker operation, and right side adrenalectomy. The surgical histopathology demonstrated prostate originated synovial sarcoma and adrenocortical carcinoma. Synovial sarcoma is a malignant soft tissue tumor and is normally seen in the adolescent and young adult population.1 Synovial sarcoma mainly involves the para-articular regions of the extremities, but other unusual sites have also been documented.1,2 The primary prostatic synovial sarcoma is extremely rare, and only a few cases have been reported to date.3,4 The lower urinary tract symptoms, including dysuria, increased urinary frequency, and nocturia, are the major clinical presentations of intraprostatic synovial sarcoma.4 Unlike prostate cancer, the serum PSA levels are usually normal in prostatic synovial sarcoma.2 The primary prostatic synovial sarcoma has an aggressive clinical course, and distant metastases to the lung and liver have been reported." Although in this case, no evidences of metastases were found. The radiological features of primary prostatic synovial sarcoma are not characteristic, which may present large hypoechoic lesion on ultrasound and soft tissue tumor with mixed cystic/solid components on CT.2,5 The adrenocortical carcinoma is an aggressive tumor with poor 5-year survival rate,6 and the majority of adrenocortical carcinoma, like this case, show hypermetabolism on 18F-FDG PET/CT.7,8 Here, we present a rare case of primary prostatic synovial sarcoma and combined adrenocortical carcinoma.

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