INTERESTING IMAGE Rare Case of Testicular Sarcoidosis Detected on FDG PET/CT in a Patient With PUO Girish Kumar Parida, MD,* Adarsh Kumar, MCh,† Sujata Mitra, DRM,* Akchata Suman, MSc,* and G. Sonai Muthu, MSc* Abstract: Genitourinary sarcoidosis is an uncommon entity, and testicular sarcoidosis is even rarer. We present a case of 66-year-old man who presented to our hospital as PUO (pyrexia of unknown origin) and later diagnosed as testicular sarcoidosis with the help of FDG PET/CT. Key Words: testicular sarcoidosis, PUO, FDG PET/CT (Clin Nucl Med 2020;45: e368–e369) Received for publication January 12, 2020; revision accepted April 10, 2020. From the Departments of *Nuclear Medicine and PET/CT, and †Surgical Oncology, Tata Main Hospital, Jamshedpur, India. Conflicts of interest and sources of funding: none declared. Correspondence to: Girish Kumar Parida, MD, Department of Nuclear Medicine and PET/CT, Tata Main Hospital, Jamshedpur 831001, India. E-mail: grissh135@gmail.com. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved. ISSN: 0363-9762/20/4508–e368 DOI: 10.1097/RLU.0000000000003120 e368 www.nuclearmed.com REFERENCES 1. Iannuzzi MC, Rybicki BA, Teirstein AS. Sarcoidosis. N Engl J Med. 2007; 357:2153–2165. 2. Rizzato G. Extrapulmonary presentation of sarcoidosis. Curr Opin Pulm Med. 2001;7:295–297. 3. Rudin L, Megalli M, Mesa-Tejada R. Genital sarcoidosis. Urology. 1974;3: 750–754. 4. Reineks EZ, MacLennan GT. Sarcoidosis of the testis and epididymis. J Urol. 2008;179:1147. 5. Karapetis CS, Strickland AH, Yip D, et al. PET and PLAP in suspected testicular cancer relapse: beware sarcoidosis. Ann Oncol. 2001;12:1485–1488. 6. Pravin K, Rao MD, Edmund S, et al. Genitourinary sarcoidosis. Cleveland Clinic Rev Urol. 2009;11:108–113. 7. McGrath DS, Daniil Z, Foley P, et al. Epidemiology of familial sarcoidosis in the UK. Thorax. 2000;55:751–754. 8. Newman LS, Rose CS, Maier LA. Sarcoidosis. N Engl J Med. 1997;336: 1224–1234. 9. Thuret R, Cariou G, Aerts J, et al. Testicular sarcoidosis with elevated levels of cancer–associated markers. J Clin Oncol. 2008;26:6007–6008. 10. Ran P, Liang X, Zhang Y, et al. FDG PET/CT in a case of bilateral tuberculous epididymo-orchitis. Clin Nucl Med. 2019;44:757–760. 11. Qureshi PAAA, Yaseen MT, Bashir H, et al. Pearls in the wrong pockets: idiopathic scrotal calcinosis. Clin Nucl Med. 2019;44:e579–e580. 12. Singh H, Sharma P, Suman KCS, et al. Post orchiectomy intrascrotal hematoma mimicking local recurrence on 18F-FDG PET/CT: a diagnostic dilemma. Clin Nucl Med. 2012;37:e102–e103. Clinical Nuclear Medicine • Volume 45, Number 8, August 2020 Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved. Clinical Nuclear Medicine • Volume 45, Number 8, August 2020 Testicular Sarcoidosis in FDG PET/CT FIGURE 1. A 66-year-old man presented to our hospital with complains of low-grade fever and weakness for last 3 months. Blood investigations showed no significant abnormality except low hemoglobin. In suspicion of hematological pathology, the patient underwent bone marrow biopsy, which showed micronormoblastic anemia with no other obvious abnormality to suggest the cause of fever. Then he underwent FDG PET/CT to look for any inflammatory/neoplastic focus. FDG PET/CT study showed mild FDG-avid subcentimetric to centimetric mediastinal lymph nodes. In addition to that focal increased FDG uptake seen in the left testes (A, MIP, black arrow), with corresponding hyperdensity on CT, measuring approximately 10  12 mm (B and E showing transaxial and coronal CT images, C and F showing corresponding fused PET images, D and G showing corresponding fused PET/CT images with arrows demonstrating the lesion). The patient was advised for few serum tumor markers that included AFP, β-HCG, and LDH, among which only AFP was found out to be borderline elevated (2.68 U/mL; range, 0.56–2.64 U/mL). Patient was also advised ANA, anti-CCP, anti-DNA antibody, which were found out to be negative. To rule out any testicular neoplastic pathology, the patient underwent left high inguinal orchidectomy, which showed a circumscribed pale cream–colored firm area with a size of 10  10  12 mm located just below the tunica albuginea on the lateral border of the testis. Microscopic examination showed normal seminiferous tubes with noncaseating granulomas (A and B showing 10 and 40 fields, respectively), favoring a diagnosis of sarcoidosis. Serum ACE was also advised, which was found out to be elevated (110 U/L), suggesting the lesion to be sarcoidosis. EBUS-guided fine-needle aspiration from the mediastinal lymph nodes also confirmed the diagnosis. FIGURE 2. A and B, Sarcoidosis is an inflammatory condition, commonly involving lungs. However, it can also involve extrapulmonary organs, including the skin, liver, spleen, eyes, lymph nodes, central nervous system, salivary glands, mucosae, joints, heart, bone marrow, muscles, and kidneys.1,2 Among these, urogenital sarcoidosis is very rare.3 To date, only about 60 cases have been described in the literature.4,5 This corresponds to approximately 0.2% of all the cases of sarcoidosis diagnosed. When the urogenital system is affected, it is usually the epididymis that is commonly involved, followed by the testis and vas deferens.6 Microscopically sarcoidosis is characterized by non-necrotizing, epithelioid cell granulomas occurring in different organs.7 The etiology is still unclear, with the onset of disease typically in young adults. Familial clustering is seen in 5% to 19% of cases, which is why a significant genetic background is assumed.8 Ours is a case of testicular sarcoidosis, showing increased FDG avidity on PET/CT imaging. Besides sarcoidosis, there are other benign causes that can show increased FDG avidity in the testes, so histopathology remains the criterion standard for diagnosis of testicular sarcoidosis.9–12 © 2020 Wolters Kluwer Health, Inc. All rights reserved. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved. www.nuclearmed.com e369