[¹⁸F]FDG PET/CT Mapping of Metastatic Spread in Left Testicular Carcinoma: A Rare Visualization of Lymphatic Pathway

Abstract

We report a rare case of metabolic visualization of the entire left testicular lymphatic drainage pathway by [¹⁸F]FDG-PET/CT (¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography) in a 22-year-old male with biopsy-proven non-seminomatous germ cell tumor (NSGCT) of the left testis, presenting with extensive metastases to the retroperitoneal lymph nodes (RPLNs), liver, lungs, and skeleton. Primary staging with [¹⁸F]FDG-PET/CT demonstrated intense radiotracer uptake in both the primary tumor and multiple metastatic sites. Notably, a rare linear pattern of [¹⁸F]FDG avidity was observed along the left testicular lymphatic drainage pathway, following the course of the left testicular vein. While the anatomical pathway of lymphatic dissemination in testicular malignancies is well-characterized and [¹⁸F]FDG avidity in RPLNs has been previously reported, direct metabolic visualization of the entire lymphatic drainage pathway on [¹⁸F]FDG-PET/CT has not been documented. This case further underscores the utility of [¹⁸F]FDG-PET/CT in the initial staging of advanced NSGCT, particularly in detecting skeletal metastases that may be subtle or occult on conventional imaging, bearing important clinical and prognostic implications.

Keywords

testicular cancer - [¹⁸F]FDG-PET/CT - metastasis - embryonal carcinoma

Authors' Contributions

A.S. and S.S.: Case data accumulation, case report drafting and revision. S.M.: Providing histopathology details including IHC findings. S.B.: Case discussion, concept guidance, and draft finalization.

Publikationsverlauf

Artikel online veröffentlicht:
14. Oktober 2025

• References

• 1 Siegel RL, Miller KD, Fuchs HE, Jemal A. Cancer statistics, 2022. CA Cancer J Clin 2022; 72 (01) 7-33
• 2 Oldenburg J, Berney DM, Bokemeyer C. et al; ESMO Guidelines Committee. Electronic address: [e-mail], EURACAN. Testicular seminoma and non-seminoma: ESMO-EURACAN Clinical Practice Guideline for diagnosis, treatment and follow-up. Ann Oncol 2022; 33 (04) 362-375
• 3 Coursey Moreno C, Small WC, Camacho JC. et al. Testicular tumors: what radiologists need to know–differential diagnosis, staging, and management. Radiographics 2015; 35 (02) 400-415
• 4 Canete Portillo S, Rais-Bahrami S, Magi-Galluzzi C. Updates in 2022 on the staging of testicular germ cell tumors. Hum Pathol 2022; 128: 152-160
• 5 EAU Guidelines. Edn. presented at the EAU Annual Congress Madrid 2025. ISBN 978-94-92671-29-5
• 6 Paño B, Sebastià C, Buñesch L. et al. Pathways of lymphatic spread in male urogenital pelvic malignancies. Radiographics 2011; 31 (01) 135-160
• 7 Sharma A. Positron emission tomography/computed tomography for diagnosis of prosthetic valve endocarditis. J Am Coll Cardiol 2013; 62 (09) 861
• 8 Hung TJ, McLean L, Mitchell C. et al. The role of ¹⁸F-FDG-PET/CT in evaluating retroperitoneal masses -keeping your eye on the ball!. Cancer Imaging 2019; 19 (01) 28
• 9 Kreydin EI, Barrisford GW, Feldman AS, Preston MA. Testicular cancer: what the radiologist needs to know. AJR Am J Roentgenol 2013; 200 (06) 1215-1225
• 10 Huddart RA, O'Doherty MJ, Padhani A. et al; NCRI Testis Tumour Clinical Study Group. 18fluorodeoxyglucose positron emission tomography in the prediction of relapse in patients with high-risk, clinical stage I nonseminomatous germ cell tumors: preliminary report of MRC Trial TE22–the NCRI Testis Tumour Clinical Study Group. J Clin Oncol 2007; 25 (21) 3090-3095
• 11 de Wit M, Brenner W, Hartmann M. et al. [18F]-FDG-PET in clinical stage I/II non-seminomatous germ cell tumours: results of the German multicentre trial. Ann Oncol 2008; 19 (09) 1619-1623
• 12 Ayati N, Askari E, Fotouhi M. et al. Nuclear medicine imaging in non-seminomatous germ cell tumors: lessons learned from the past failures. Cancer Imaging 2024; 24 (01) 156
• 13 Gille R, Allignet B, Izarn F, Peyrat P, Boyle H, Fléchon A. Bone metastases in non-seminomatous germ cell tumors: a 20-year retrospective analysis. J Clin Med 2024; 13 (11) 3280
• 14 Oing C, Oechsle K, Necchi A. et al. Impact of primary metastatic bone disease in germ cell tumors: results of an International Global Germ Cell Tumor Collaborative Group G3 Registry Study. Ann Oncol 2017; 28 (03) 576-582
• 15 Gillessen S, Sauvé N, Collette L. et al; International Germ Cell Cancer Classification Update Consortium. Predicting outcomes in men with metastatic nonseminomatous germ cell tumors (NSGCT): results from the IGCCCG Update Consortium. J Clin Oncol 2021; 39 (14) 1563-1574