a 65-year - old woman was referred to our department because of a recently diagnosed left atrial ( la ) mass .
she presented with a five - month history of fever , malaise , and myalgia and had been diagnosed with ventricular septal defect ( vsd ) two years earlier . on physical examination ,
two - dimensional transthoracic echocardiography showed an la cyst ( 2423 mm ) that was attached to the interatrial septum and detected the trace of blood flow at the margin of the cyst ( fig .
1 ) . the vsd was a small perimembranous type and the pulmonary blood flow to systemic blood flow ratio ( qp / qs ) was 1.2 . the patient underwent surgical treatment .
the cystic mass attached to the left side of the interatrial septum was white - pink - yellowish and oval in shape .
the cystic mass was widely excised with the atrial septum , leaving the defect in the atrial septum , and the small vsd was closed with two pledgeted sutures without a patch .
the defect on the atrial septum was closed with an artificial patch ( polytetraflouroethylene , gore - tex patch ; wl gore & assoc , flagstaff , az , usa ) .
histologically , the mass consisted of myxoid cells in abundant loose and myxoid stroma , and the tumor cells were round or polygonal with eosinophilic cytoplasm ( fig .
la myxoma is usually a solid , round or polypoid mass without a cystic structure attached to the interatrial septum .
the size of the mass ranges from 1 to 15 cm and is usually about 5 to 6 cm .
the mass has solid content with a consistency varying according to the amount of collagen it contains .
the preoperative diagnosis of a cardiac mass has been enabled by echocardiographic examination . in this case , it was difficult to establish the diagnosis of the mass preoperatively because of its cystic structure without any content .
however , we believed that it was not a simple cyst and that surgical excision was needed because she had had constitutional symptoms .
myxomas originated from the mesenchymal cells of the septal endocardium and can present as villous , papillary , sessile or pedunculated pattern and were usually divided into round and polypoid type and the majority of them are solid .
the types of cystic masses that can appear in la are as follows : myxoma , hydatid cyst , and interatrial septal aneurysm [ 5 - 8 ] . owing to their many structural similarities , it is difficult to establish an accurate diagnosis using preoperative echocardiography .
major complications like stroke , rupture , and hemodynamic problems may develop if they are not removed .
therefore the surgical excision of an la cyst is reasonable for establishing a definitive diagnosis and preventing sequelae .
 cardiac myxomas are the most common primary benign tumors of uncertain etiology 
 . they usually present as polypoid or oval - shaped masses projecting into a heart chamber from the interatrial septum and have a soft , gelatinous consistency without a cystic structure . 
 we report a case of left atrial myxoma with a single cystic form . 
CASE REPORT
DISCUSSION