Rapid growth of calcified amorphous tumor with mitral annulus calcification: a case report.

Background: Calcified amorphous tumor (CAT) of the heart is a rare, non-neoplastic cardiac mass with mitral valves and annuli being the most common sites. The presence of mitral annular calcification (MAC) is associated with an increased risk of stroke or other systemic embolisms. Here, we report a case of CAT showing rapid growth with MAC and investigate the link between the two.

Case presentation: A 71-year-old man presented at our hospital with dyspnea and had been undergoing hemodialysis for 26 years for chronic glomerulonephritis. Transthoracic echocardiography (TTE) revealed moderate mitral stenosis with bulky MAC. Two months later, the patient developed progressive dyspnea, and follow-up TTE revealed a highly mobile mass (8 × 5 mm) attached to the left ventricular (LV) side of the posterior MAC. He underwent surgery because of congestive heart failure and a high risk of embolization. Surgical inspection revealed that the tumor was attached beneath the P3 segment of the mitral valve on the LV side and was removed. When removing the MAC, toothpaste-like contents drained from the encapsulated mass inside the MAC at the P3 segment, where the tumor was located. After reconstructing the posterior mitral annulus defect with a bovine pericardial patch, mitral valve replacement with a mechanical prosthesis, a maze procedure, and left appendage closure were performed. Histopathological examination revealed that the excised tumor contained fibrin and calcium deposits. The mass was diagnosed as a CAT.

Conclusions: CAT may be one of the causes of stroke induced by MAC. Routine follow-up echocardiography should be recommended for patients with MAC, especially those undergoing hemodialysis.