We experienced a very rare case in a 26-year-old man who underwent surgery for bilateral atrial myxomas. Moreover, his initial symptoms were due to acute myocardial infarction, which strongly suggested coronary artery embolization. Transesophageal echocardiography revealed not only left atrial myxoma at posterior wall, but also right atrial myxoma at the fossa ovalis which had not been detected by transthoracic echocardiography. At surgery, both left and right atriotomy was performed and bilateral atrial myxomas were completely removed. We emphasized that transesophageal echocardiography was very useful in detecting the location of myxomas, and that surgical exploration of the right atrium would have been necessary even if left atrial myxomas had not existed at the atrial septum.

Fibroblast growth factor 23 (FGF23) is a pivotal humoral factor for the regulation of serum phosphate levels and was first identified in patients with autosomal dominant hypophosphatemic rickets and tumor-induced osteomalacia (TIO), the most common form of acquired FGF23-related hypophosphatemic rickets/osteomalacia (FGF23rHR). After the identification of FGF23, many other inherited and acquired forms of FGF23rHR were reported. In this review article, the detailed features of each acquired FGF23rHR are discussed, including TIO, ectopic FGF23 syndrome with malignancy, fibrous dysplasia/McCune-Albright syndrome, Schimmelpenning-Feuerstein-Mims syndrome/cutaneous skeletal hypophosphatemia syndrome, intravenous iron preparation-induced FGF23rHR, alcohol consumption-induced FGF23rHR, and post-kidney transplantation hypophosphatemia. Then, an approach for the differential diagnosis and therapeutic options for each disorder are concisely introduced. Currently, the majority of endocrinologists might only consider TIO when encountering patients with acquired FGF23rHR; an adequate differential diagnosis can reduce medical costs and invasive procedures such as positron emission tomography/computed tomography and venous sampling to identify FGF23-producing tumors. Furthermore, some acquired FGF23rHRs, such as intravenous iron preparation/alcohol consumption-induced FGF23rHR, require only cessation of drugs or alcohol to achieve full recovery from osteomalacia.