Anatomical Mapping of Lymphatic Leakage Leading to Symptomatic Lymphoceles Formation After Pelvic Lymph Node Dissection for Prostate Cancer

PURPOSE: The role of pelvic lymph node dissection (PLND) during radical prostatectomy (RP) remains controversial. PLND morbidity, particulary lymphocele formation, is the main argument against PLND, despite level one evidence demonstrating metastasis reduction with extended PLND. The aim of this study is to identify the precise anatomical sites and mechanisms of lymphocele formation after RP and to propose preventive surgical modifications. METHODS: In this prospective, single-center study, we included patients who developed symptomatic lymphoceles after RP with extended PLND or salvage PLND between 2018 and 2024. All underwent ultrasound- and fluoroscopy-guided lymphangiography with or without lymphatic leak embolization (LLE). Leak sites were classified by anatomical location along the pelvic lymphatic drainage pathway. The primary outcome was precise anatomical localization of lymphatic leakage. RESULTS: Forty patients with 45 lymphoceles were evaluated. Lymphangiography identified active leakage in 43/45 lymphoceles (96%). The Cloquet region accounted for 42/43 (98%; 95% CI 88-100%) leak sites. Among single-site Cloquet leaks (n=41), 73% arose from afferent vessels draining into and excised Cloquet's node, 17% from efferent vessels with intact Cloquet, and 9.8% from partially excised Cloquet. Clinical success of LLE was achieved in 84% of cases. CONCLUSIONS: In prostate cancer, Cloquet's node is rarely metastatic (<1%), yet it is overwhelmingly (98%) the most common site of lymphatic leak leading to lymphocele formation after RP. Cloquet-sparing PLND with meticulous lymphostasis may reduce lymphatic leakage and lymphocele-related morbidity without compromising oncologic control. Prospective comparative studies are warranted to validate this finding.