A 31-year-old man referred with six to seven years' history of a left-side WHO grade III varicocele and normal palpatory abdominal findings underwent microsurgical subinguinal varicocelectomy. At 3-month follow-up there was complete remission. The varicocele recurred after one year and abdominal ultrasound demonstrated a solid mass in the left kidney. A radical nephrectomy was performed and histology demonstrated renal cell carcinoma pT2. We recommend performing an abdominal ultrasound in adults if recurrence of a varicocele is detected following microsurgical subinguinal varicocelectomy.