Discharging loin sinus: Unusual manifestation of ruptured horseshoe kidney

We present a 20-year-old man with a chronic discharging sinus in the left loin arising from a horseshoe kidney with a large pelvicalyceal calculus on its left side. The left moiety was non-functional, so a left hemi-nephrectomy, together with excision of the whole fistula tract, was carried out. Histopathology was suggestive of chronic interstitial nephritis. Patients with horseshoe kidney are prone to development of renal stones and their associated complications. The unfamiliar anatomy of horseshoe kidneys may increase the complexity of any surgical procedure. Radiological investigations are pivotal in identification of the underlying renal pathology; they may also delineate a fistula tract as in our case.