Vascular transformation of the lymph node sinuses (VTS) is an uncommon phenomenon that is believed to occur secondary to obstruction of efferent lymphatics, frequently occuring in retroperitoneal lymph nodes draining cancer. The nodular subtype of VTS, in particular, can mimic metastatic cancer, such as metastatic renal cell carcinoma with sarcomatoid differentiation, potentially resulting in inaccurate tumor grading and/or staging. We present a case of nodular VTS mimicking metastatic renal cell carcinoma with sarcomatoid differentiation in a patient with high-grade clear cell renal cell carcinoma, and explore the relevant differential diagnosis. Awareness of VTS is essential to avoid misdiagnosis of this benign and curative condition.
Keywords: clear cell renal cell carcinoma; high-grade renal cell carcinoma; metastatic renal cell carcinoma; sarcomatoid differentiation; sarcomatoid renal cell carcinoma; vascular proliferations; vascular transformation of lymph node sinuses.