International Urology and Nephrology 34: 485–487, 2002. © 2003 Kluwer Academic Publishers. Printed in the Netherlands. 485 Radiopaque shadow in the lumbar region on plain X-ray abdomen: Diagnostic dilemma P.N. Dogra, M.S. Ansari, Apul Goel, Rajendra Prashad & Sanjay Sharma Departments of Urology, Surgery, and Radiology, All India Institute of Medical Sciences, New Delhi, India Abstract. A 28-year-old man presented with right flank pain. Radiological investigations suggested the diagnosis of a calcified mass in the retroperitoneum below the right kidney. Laparoscopic exploration using the retroperito- neoscopic approach was performed. However, it was not possible to locate the lesion and an open exploration was done. During exploration a large fecolith was found trapped in a diverticulum of the cecum. Key words: Cecum, Diverticulum, Fecolith Introduction A calcified fecolith may simulate a retroperitoneal tumor and pose diagnostic difficulties even after the use of modern diagnostic investigations. We describe an interesting case in which radiological investiga- tions suggested the diagnosis of a calcified mass in the retroperitoneum below the right kidney, which turned out to be a fecolith located in a solitary cecal diverticulum. Case report A 28-year old male presented with complaints of right flank pain of 4 months duration. There was no history of constipation or spinal tuberculosis. He had a right ureteric stone for which ureteroscopic removal followed by double J (DJ) stenting was done 18- months back. Biochemical evaluations were normal. Plain X-ray abdomen revealed a large radiopaque shadow opposite right L4 vertebra. Suspecting it to be a fecolith the patient was given bowel preparation with polyethylene glycol-electrolyte solution and an X-ray repeated. However, the shadow did not disappear. Ultrasound evaluation revealed normal kidneys and a calcified mass in the retroperitoneum below the right kidney. An intravenous urogram (IVU) revealed normal kidneys (Figure 1). CT scan abdomen revealed a calcified mass in the retroperitoneum, however, the nature of the lesion could not be commented Figure 1. Intravenous urogram demonstrating normal urinary tracts with the radiopaque shadow (arrow) located below the right kidney.