A case of pure matrix ureteral stone : a rare type of urinary calculi that may be overlooked

Abstract EN

Matrix stones are a rare form of urinary calculi with a low mineral content.

We report a 63-year-old female patient who presented to the Sohar Hospital, Sohar, Oman, in 2018 with unexplained left flank pain and constipation.

She had a history of chronic renal failure (CRF) and had previously undergone haemodialysis (HD).

Non-contrast computed tomography (CT) did not show any renal or urinary stones.

However, a left-sided ureteroscopy revealed a yellow-coloured stone that was soft in consistency occupying the proximal 5 cm section of the ureter.

Many attempts at forceps extraction were required for complete clearance.

A global quantitative composition analysis revealed the extracted stone to be composed entirely of protein-matrix material.

Matrix stones require a high index of suspicion as they are sometimes radiolucent and cannot be visualised on CT scans.

Risk factors include being female and a history of urinary tract infections, CRF and HD.