Calcified amorphous tumor in the left atrium in a patient on long-term peritoneal dialysis.

A 66-year-old woman with an 11-year history of peritoneal dialysis (PD) for diabetic nephropathy and renal failure exhibited a movable tumor in the left atrium on echocardiography. Tumor resection was performed due to the difficulty in diagnosing the tumor and the future risk of heart failure and embolization. Light microscopy showed a calcified amorphous tumor (CAT), a rare intracardiac mass characterized by the presence of a pedicle and diffuse calcification. An increased calcium-phosphate product level was suspected as an etiology, although degeneration, inflammation and/or mineral balance disorders may also induce the development of CAT. We herein report the first known case of CAT in a PD patient.