Intraoperative frozen pathological diagnosis of cystic tumor of the atrioventricular node: a case report and review of the literature.

Cystic tumor of the atrioventricular node is an extremely rare primary tumor of the heart. Here we report a case of a 41-year-old female who presented with dizzy and palpitations. Electrocardiography revealed third-degree atrioventricular block. Echocardiography and Chest computed tomography showed a mass attached to the interatrial septum. Intraoperative frozen pathological examination revealed that the mass was the cystic tumor of the atrioventricular node. The diagnosis was proved by histopathology and immunohistochemistry. This is the first case that was diagnosed dependent on frozen pathological examination and treated successfully with surgery.