Renal cell carcinoma arising from a horseshoe kidney in a chronic hemodialysis patient.

A 60-year-old man undergoing hemodialysis for 13 years was referred to our department for evaluation of gross hematuria and a right renal mass. Voided urine cytology was negative. Computed tomography and magnetic resonance imaging demonstrated a right renal mass (32 × 22 × 20 mm in diameter). We clinically diagnosed the tumor as renal cell carcinoma staged T1aN0M0 arising from a horseshoe kidney, and performed right heminephrectomy. Pathological examination of the surgical specimen showed a grade 2, pT1a, clear cell carcinoma and negative surgical margin. To our knowledge, this is a rare case of a renal cell carcinoma arising from a horseshoe kidney in a chronic hemodialysis patient.