An Unusual Case of Uremic Tumoral Calcinosis with Atypical Manifestation in a Patient on Peritoneal Dialysis: Case Report and Review of the Literature

Background: Uremic tumoral calcinosis (UTC) is a rare yet severe complication of chronic kidney disease (CKD), predominantly occurring in patients undergoing renal replacement therapy (RRT). It is characterized by extensive soft tissue calcifications, frequently associated with chronic hyperphosphatemia and disruptions to calcium–phosphorus metabolism. Case report: This report describes a 34-year-old woman with end-stage renal disease (ESRD) secondary to lupus nephritis, undergoing continuous ambulatory peritoneal dialysis (CAPD). She presented with a progressively enlarging calcified mass in the proximal phalanx of the third finger on her right hand, accompanied by functional impairment. Laboratory findings revealed persistent hyperphosphatemia (8.8 mg/dL), elevated parathyroid hormone levels (901 pg/mL), and low vitamin D levels (9 ng/mL), indicating significant disturbances to mineral metabolism. Imaging studies, including X-ray and whole-body 18F-Choline positron emission tomography/computed tomography (PET/CT), confirmed the presence of localized calcifications in the soft tissue of the proximal phalanx of the third finger on her right hand and parathyroid hyperplasia, respectively. Initial management included the optimization of phosphate binders and calcimimetic therapy, with the subsequent intensification of dialysis therapy. Transitioning to automated peritoneal dialysis (APD) with high-volume exchanges resulted in a notable improvement in biochemical parameters and the eventual remission of the calcified mass. Conclusion: This case underscores the importance of comprehensive management in dialysis patients, including dietary phosphate restriction, the appropriate use of non-calcium-based binders, and tailored dialysis regimens to prevent and treat CKD-related mineral and bone disorders. It also highlights the utility of imaging modalities such as PET/CT in diagnosing UTC and monitoring response to therapy. Further research is needed to elucidate the pathophysiology of UTC and optimize its management in dialysis patients.