A case of temporary metastatic pulmonary calcification in a patient with hyperparathyroidism on peritoneal dialysis

Introduction Ectopic calcification is associated with secondary hyperparathyroidism (HPT) in patients with end-stage renal failure (ESRD). Metastatic pulmonary calcification (MPC) is another rare type of ectopic calcification, and there are a few reports on MPC in dialysis patients. Case presentation We report the case of a 52-year-old woman admitted with general fatigue and appetite loss, who was on peritoneal dialysis (PD) for 7 years. Although she was initially suspected of having secondary HPT due to ESRD, we finally diagnosed ectopic HPT that was caused by a cystic mass behind her thyroid gland overlapping with secondary HPT. We carefully observed her under conservative therapy because she refused surgery. On admission, she was diagnosed as having MPC because she had ground-glass-like opacification in her lung fields on high-resolution computed tomography scan, which was caused by a parathyroid tumor complicated by secondary HPT associated with ESRD. After she began intravenous injection of etelcalcetide hydrochloride, serum calcium, and intact parathyroid hormone (iPTH), values were adjusted, and the opacification disappeared. Conclusion In a patient on PD, this is the first case of MPC that developed due to acute hypercalcemia, hyperphosphatemia, and dehydration and in which the ectopic pulmonary calcification clearly decreased with optimization of iPTH.