Vol.:(0123456789) 1 3 General Thoracic and Cardiovascular Surgery https://doi.org/10.1007/s11748-020-01363-w CASE REPORT Calcifed amorphous tumor with caseous calcifcation of mitral annulus in hemodialysis patients Shinji Kanemitsu 1  · Saki Bessho 2  · Shunsuke Sakamoto 1  · Naoki Yamamoto 2  · Hisato Ito 2  · Hideto Shimpo 2 Received: 6 March 2020 / Accepted: 7 April 2020 © The Japanese Association for Thoracic Surgery 2020 Abstract Mitral annular calcifcation (MAC) is a common fnding, especially among the elderly. Caseous calcifcation of the mitral annulus (CCMA) is a rare variant of MAC. Calcifed amorphous tumor (CAT) is an extremely rare non-neoplastic cardiac tumor accompanied by calcifcation and is often associated with MAC. We encountered two patients with end-stage renal failure in whom a cardiac CAT developed on the mitral annulus. In both patients, preoperative examination showed MAC of the posterior mitral annulus and a mobile mass attached to the MAC. CAT and CCMA were considered, and surgical resec- tion was performed because of a high risk of systemic embolization. Intraoperatively, the mobile mass was associated with the CCMA. The CCMA with the mass was entirely removed, and the diagnosis of CAT was histologically confrmed. We herein report these two cases of CAT arising from CCMA in patients undergoing hemodialysis and propose the characteristic imaging features and operative fndings. Keywords Calcifed amorphous tumor · Caseous calcifcation of mitral annulus · Mitral annular calcifcation Introduction Mitral annular calcifcation (MAC) is defned as chronic degenerative changes of the fbrous skeleton of the mitral valve annulus. Caseous calcifcation of the mitral valve annulus (CCMA) is a rare variant of MAC. It is similar in appearance to cysts, thrombi, tumors, or abscesses. Moreo- ver, calcifed amorphous tumor (CAT) is a very rare non- neoplastic cardiac tumor with an unclear clinical manifesta- tion and treatment. CCMA should, therefore, be considered a diferential diagnosis of other similarly appearing lesions. Case 1 A 77-year-old man undergoing hemodialysis for 10 years was referred to our hospital for evaluation of intracardiac masses. Transthoracic echocardiography revealed cardiac mass adherent to MAC in the posterior annulus with a smooth surface and central echolucency (Fig. 1a). Computed tomography (CT) showed the 35-mm-diameter high-density tumor (Fig. 1b). Based on its characteristic features, the mass was suspicious for CCMA associated with MAC. Although the patient was asymptomatic and had no remarkable infam- matory changes, he underwent surgical resection because of the high risk of embolization. Toothpaste-like liquefac- tion was suctioned from the mass, compatible with CCMA. Because the MAC deeply involved the mitral annulus and left ventricular muscle, we performed complete decalcif- cation using a cavitron ultrasonic surgical aspirator. After debridement of the annular cavity, the neo-posterior annulus was reconstructed with a pericardial patch and a biopros- thetic valve (St. Jude Medical, St. Paul, MN) was implanted (Fig. 1c, Video). Histological examination showed that the tumor contained multiple calcifed nodules, confrming the diagnosis of CAT (Fig. 1d). No further embolic events had occurred at the 1.5-year follow-up. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s11748-020-01363-w) contains supplementary material, which is available to authorized users. * Shinji Kanemitsu skanemitsu70@gmail.com 1 Department of Cardiovascular Surgery, Anjo Kosei Hospital, Higashihirokute-28 Anjo-cho , Anjo, Aichi 446-8602, Japan 2 Department of Thoracic and Cardiovascular Surgery, Mie University Graduate School of Medicine, Tsu, Mie 514-8507, Japan