Objective To analyze the clinical characteristics of renal cell carcinoma patients with extracapsular segmental vein tumor thrombus during partial nephrectomy and to explore the clinical significance,thereby contributing to an advanced comprehension of the pathogenesis of cancer thrombus in renal cell carcinoma.Methods A retrospective analysis was conducted on the clinical data of 209 renal cell carcinoma patients(162 with T1a stage,47 with T1b stage)who underwent partial nephrectomy in our hospital during Sep.2023 and Jul.2025.Among them,8 patients with extracapsular segmental vein tumor thrombus were identified,and the clinical and pathological characteristics were analyzed.Results Among the 8 cases of extracapsular segmental vein tumor thrombus,1 was in T1a stage and 7 were in T1b stage.Preoperativc CT revealed roundish,solid renal masses with heterogeneous density on non-contrast scans,significant enhancement on contrast-enhanced scans,and markedly weaker enhancement in the renal parenchymal phase compared to normal renal tissue.The average tumor diameter was(4.9±0.2)cm,with clear boundaries and no evidence of vascular invasion.Postoperative pathology confirmed clear cell carcinoma in all cases,with International Society of Urological Pathology(ISUP)grades ranging from Ⅰ to Ⅳ,and all surgical margins were negative.After surgery,5 patients received adjuvant immunotherapy.In a median follow-up of 10.3(3.8-22.8)months,no tumor recurrence or metastasis was observed.Conclusion Renal cell carcinoma has a high propensity of vascular invasion,and even clinically staged T1 tumors may develop extracapsular segmental vein tumor thrombus.This finding is significant for clinical prognosis.

Objective To analyze the clinical characteristics of renal cell carcinoma patients with extracapsular segmental vein tumor thrombus during partial nephrectomy and to explore the clinical significance,thereby contributing to an advanced comprehension of the pathogenesis of cancer thrombus in renal cell carcinoma.Methods A retrospective analysis was conducted on the clinical data of 209 renal cell carcinoma patients(162 with T1a stage,47 with T1b stage)who underwent partial nephrectomy in our hospital during Sep.2023 and Jul.2025.Among them,8 patients with extracapsular segmental vein tumor thrombus were identified,and the clinical and pathological characteristics were analyzed.Results Among the 8 cases of extracapsular segmental vein tumor thrombus,1 was in T1a stage and 7 were in T1b stage.Preoperativc CT revealed roundish,solid renal masses with heterogeneous density on non-contrast scans,significant enhancement on contrast-enhanced scans,and markedly weaker enhancement in the renal parenchymal phase compared to normal renal tissue.The average tumor diameter was(4.9±0.2)cm,with clear boundaries and no evidence of vascular invasion.Postoperative pathology confirmed clear cell carcinoma in all cases,with International Society of Urological Pathology(ISUP)grades ranging from Ⅰ to Ⅳ,and all surgical margins were negative.After surgery,5 patients received adjuvant immunotherapy.In a median follow-up of 10.3(3.8-22.8)months,no tumor recurrence or metastasis was observed.Conclusion Renal cell carcinoma has a high propensity of vascular invasion,and even clinically staged T1 tumors may develop extracapsular segmental vein tumor thrombus.This finding is significant for clinical prognosis.