Renal bone metaplasia: an incidental negligible finding or a disease to treat?

Renal bone metaplasia (RBM) is a uncommon condition and is often an incidental finding. The pathogenesis of this phenomenon is not clearly understood. The radiological signs described are not always present and the diagnosis is challenging. In the literature, there is no any conclusion about the optimal management of this condition due to the absence of some conclusions regarding its etiology. In our opinion, no treatment should be applied to prevent its possible evolution into urolithiasis. Surgical removal of the RBM is an overtreatment for a phenomenon not understood and potentially insignificant. We report our experience with a watchful waiting approach in a case of incidental diagnosis of RBM. After 3 years, the patient is asymptomatic, with no evidence of malignancies evolution, new renal stones or growth of the residual RBM.