CASE REPORT

Left atrial myxoma mimicking papillary fibroelastoma

Takeshi Oda • Hiroshi Yasunaga • Tohru Takaseya •

Mau Amako • Takemi Kawara • Kageshige Todo •

Hideki Tashiro • Yoshinori Naito • Koichi Higaki

Received: 13 October 2011 / Accepted: 17 January 2012 / Published online: 15 March 2012

� The Japan Society of Ultrasonics in Medicine 2012

Abstract A 67-year-old woman was referred to our hos-

pital with a diagnosis of deep vein thrombosis due to surgery

for left patellar fracture. Deep vein thrombosis resolved with

thrombolytic therapy. Transthoracic echocardiogram

revealed a mobile left atrial tumor. Transesophageal echo-

cardiography showed a fragile tumor with multiple fronds,

implying a papillary fibroelastoma. Because this patient had

a history of cerebral embolism, urgent surgery was sched-

uled. The excised tumor showed a sea anemone-like

appearance in saline, which was similar to that of a papillary

fibroelastoma. However, histological examination revealed

the features of a myxoma and not papillary fibroelastoma.

Herein, we illustrate a very rare case of left atrial myxoma

with papillary fibroelastoma-like features in terms of both

echocardiographic and gross findings.

Keywords Papillary fibroelastoma � Myxoma �Transesophageal echocardiography

Introduction

Primary cardiac tumors are rare, with an incidence of

0.0017–0.19% in unselected patients. About three-quarters

of primary cardiac tumors are benign, and nearly 50% of

these are myxomas [1].

Papillary fibroelastoma (PFE) is the third most common

benign cardiac tumor and usually originates from the val-

vular tissue [2]. PFE has characteristic echocardiographic,

macroscopic, and histopathological features [3]. Herein, we

present a case of a tumor with histological characteristics

of a myxoma even though its echocardiographic and gross

appearance was similar to that of PFE.

Case report

A 67-year-old woman without any previous history of heart

disease was referred to our hospital with a diagnosis of

deep vein thrombosis (DVT) due to surgery for left patellar

fracture. DVT resolved with thrombolytic therapy. Trans-

thoracic echocardiography (TTE) revealed a mobile left

atrial tumor (Fig. 1). Interleukin-6 level was within

the normal limit. For further inspection, transesophageal

echocardiography (TEE) was performed. TEE results sug-

gested a fragile left atrial tumor with multiple fronds,

14 9 10 mm in size, adhering to the lower part of the atrial

septum (Fig. 2). Judging from the appearance of the tumor

on TTE and TEE, PFE was suspected rather than myxoma.

Brain computed tomography showed cerebral infarction in

the left basal nucleus. Because this patient had a history of

cerebral embolism, we urgently resected the cardiac tumor.

At surgery, median sternotomy was performed and car-

diopulmonary bypass was established via aorto-bicaval

cannulation. The left atrium was opened via the transseptal

T. Oda (&) � H. Yasunaga � T. Takaseya � M. Amako �T. Kawara � K. Todo

Department of Cardiovascular Surgery,

St. Mary’s Hospital, 422 Tsubukuhon-machi,

Kurume, Fukuoka 830-8543, Japan

e-mail: oda@st-mary-med.or.jp

H. Tashiro

Department of Cardiology, St. Mary’s Hospital,

422 Tsubukuhon-machi, Kurume,

Fukuoka 830-8543, Japan

Y. Naito � K. Higaki

Department of Pathology, St. Mary’s Hospital,

422 Tsubukuhon-machi, Kurume,

Fukuoka 830-8543, Japan

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J Med Ultrasonics (2012) 39:173–175

DOI 10.1007/s10396-012-0358-7

approach. Although the stalk was not obvious, the tumor

originated from the lower part of the atrial septum. The

surface of the tumor showed villous properties. The mass

was excised completely, including the surgical margin of

the atrial septum around the tumor. The defect in the atrial

septum after tumor resection was closed with an autolo-

gous pericardial patch. When placed in saline, the excised

tumor showed a sea anemone-like appearance with multi-

ple fronds, which was similar to the appearance of PFE

(Fig. 3). Microscopically, the lesion was composed of

spindle or small cell and glandular structures. These tumor

cells were scattered in a loose myxoid stroma. There was

no fibrous-elastic core (Fig. 4). Immunohistochemical

staining showed positive findings for calretinin, a marker

for cardiac myxoma [4] (Fig. 5). The postoperative course

was uneventful. Postoperative TTE revealed no residual

cardiac tumor.

Discussion

Papillary fibroelastoma is a rare benign cardiac tumor that

mainly originates from heart valve tissue, and it may cause

thromboembolism or mechanical interference with valvular

function. The gross appearance of PFE resembles that of a

sea anemone placed in saline. Echocardiographic findings

showed a well-demarcated, homogeneous, and speckled

Fig. 1 Preoperative transthoracic echocardiogram (parasternal long

axis view). Transthoracic echocardiography showed a left atrial tumor

(arrow) attached to the lower part of the interatrial septum. LA left

atrium, LV left ventricle

Fig. 2 Preoperative transesophageal echocardiogram. Transesopha-

geal echocardiography demonstrated a left atrial tumor with multiple

fronds (arrow). LA left atrium, Ao aorta

Fig. 3 Macroscopy of the resected tumor. When placed in saline, the

resected tumor showed a sea anemone-like appearance with multiple

fronds

Fig. 4 Histopathological image after H&E staining, 9100. The

tumor cells were scattered in a loose myxoid stroma and there was no

fibrous-elastic core

174 J Med Ultrasonics (2012) 39:173–175

123

appearance with stippling around the perimeter when the

image quality was optimal [5]. In the present case, both the

gross and echocardiographic findings of the cardiac tumor

were similar to those of a PFE.

Left heart PFE frequently presents with embolic neu-

rological symptoms. Ngaage et al. [6] reported that the

mean tumor volume in patients who had thromboembolism

was less than that in patients without thromboembolism,

probably because tumor volume decreases with the epi-

sodes of embolism. They also mentioned that since the

common location of the PFE is in the high-flow and high-

pressure systemic outflow tract of the heart, the risk of

thromboembolism is comparatively higher than that of

common benign heart tumors, e.g., atrial myxoma [5]. In

our case, the size of the tumor was relatively small and the

patient had a history of cerebral embolism. Moreover,

preoperative TTE and TEE showed a mobile and fragile

tumor. All these findings, except the tumor location, were

compatible with those of PFE.

Echocardiography is a convenient and noninvasive

examination tool. With increasing use of echocardiogra-

phy, preoperative differential diagnosis of cardiac tumors

has become more accurate. TEE is a valuable device that

uses high-resolution imaging for detailed examination of

the type of cardiac tumor. The preoperative information is

critical to the surgeon in planning the operative procedure

as well as postoperative assessment [7]. A case–control

study [8] suggested that the sensitivity and specificity of

TTE were 88.9 and 87.8%, respectively, with an overall

accuracy of 88.4% for the detection of PFE[0.2 cm. When

PFE \0.2 cm were included in the analysis, the overall

sensitivity of TTE was 61.9% and that of TEE was 76.6%.

These data imply that TEE has the advantage over TTE,

especially for small cardiac tumors. Because PFE is

generally a small tumor, TEE has been recommended to

differentiate a myxoma from a PFE. However, we mis-

diagnosed the present tumor as a PFE even after using

TEE. In general, histological examination demonstrates

that PFE is covered by endothelium that surrounds a layer

of acid mucopolysaccharide and an inner vascular core of

connective tissue [8]. In this case, such typical findings of

PFE were not seen. Moreover, immunohistological staining

demonstrated positive findings for calretinin, which can be

used as a marker for the diagnosis of cardiac myxoma [4].

Hence, we diagnosed the present case as cardiac myxoma.

Ha et al. [9] reported more frequent occurrence of systemic

embolism in polypoid myxomas than round ones. How-

ever, the gross finding in the present case was totally dif-

ferent from that of a polypoid-type myxoma.

Conclusion

We reported an extremely rare case of left atrial myxoma

with gross and echocardiographic features similar to those

of PFE.

Acknowledgments The authors are grateful to Hatsue Ishibashi-

Ueda for her pathological consultation and Andrew Hamilton for his

assistance in editing the manuscript.

Conflict of interest None declared.

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Fig. 5 Histopathological image after immunoperoxidase staining,

9200. The tumor cells expressed calretinin, a marker of cardiac

myxoma

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