Urinary matrix calculi: our experience at a single institution

Matrix stones are an uncommon form of urinary calculi and may be mistaken for tumors involving the renal collecting system, thereby presenting a diagnostic and therapeutic dilemma to the practicing urologist.

From 1980 to 2003 we identified 5 patients with urinary matrix stones referred to our tertiary medical center for evaluation and treatment.

All 5 cases had complex clinical and radiographic features at presentation. We outline the clinical presentations, imaging findings and management, and review the literature of matrix stone disease.

A high index of suspicion is required in diagnosing matrix calculi in addition to carefully selected radiographic imaging. Due to their variable appearance in standard radiological studies, the evaluation of matrix stones may require invasive techniques such as ureteroscopy for accurate diagnosis. Percutaneous removal is the primary treatment modality to render patients stone-free.