A rapidly growing cardiac calcified amorphous tumour diagnosed after coronary artery bypass graft surgery: a case report

BACKGROUND: A cardiac calcified amorphous tumour (CAT) is a non-neoplastic intracavitary cardiac mass. The most serious complication is systemic embolism. Cardiac CATs tend to be surgically resected immediately after detection; therefore, its progress of growth is rarely reported. CASE SUMMARY: An 83-year-old Japanese woman received on-pump beating coronary artery bypass graft surgery (CABG) for angina pectoris. Transthoracic echocardiography (TTE) performed preoperatively and 1 month postoperatively revealed the presence of mitral annular calcification, with no other abnormal findings. However, follow-up TTE performed 5 months after CABG revealed a mobile nodular mass (5.0 × 8.2 mm) in the left ventricular outflow tract. At 1 month after detection, the mass had enlarged to 5.0 × 13.0 mm. Transoesophageal echocardiography revealed that the pedunculated high-echoic mass was adhered to the posterior commissure of the mitral valve and was dynamically swinging towards the non-coronary cusp in the systolic phase. As the mass had grown rapidly in less than 6 months, it was surgically resected to prevent systemic embolism. The histological specimen consisted mainly of fibrin, including calcification and hemosiderin deposition, which lead to a diagnosis of cardiac CAT. The patient had an uneventful postoperative course during her hospital stay and had no evidence of recurrence for 1 year after discharge. DISCUSSION: This was a rare case in which a rapidly growing cardiac CAT was detected following on-pump CABG. Cardiac CATs may grow very rapidly and therefore early surgery should be considered after initial diagnosis.