Surgical Resection of a Calcified Amorphous Tumor of a Mitral Valve Leaflet with Distinct Imaging Features

INTRODUCTION: A calcified amorphous tumor (CAT) is a rare non-neoplastic intracardiac mass, and its preoperative diagnosis remains challenging because of its overlap with other cardiac lesions. CASE PRESENTATION: A 68-year-old woman was referred for evaluation of a calcified mass confined to the posterior mitral leaflet. Serial non-contrast CT over 5 years demonstrated progressive enlargement of the lesion together with dynamic internal changes, including loss of central calcification. Given the history of cerebral infarction and potential risk of thromboembolism, surgical resection was performed. The mass and mitral valve were resected, followed by mitral valve replacement. Histopathological examination confirmed the diagnosis of a CAT. The postoperative course was uneventful, and no recurrence was observed during 10 years of follow-up. CONCLUSIONS: This case represents a rare CAT confined to the posterior mitral leaflet without mitral annular calcification or dialysis dependence. Pathological examination suggested cavitary degeneration corresponding to the serial CT changes. Serial imaging findings may provide valuable clues for preoperative diagnosis and surgical decision-making.