Left atrium mass in a patient with breast cancer: a case report
Sugawara et al. Journal of Medical Case Reports
Left atrium mass in a patient with breast cancer: a case report
Yu Sugawara 0
Ryuji Okamura 2
Shigeki Taniguchi 1
0 Department of Internal Medicine, Yamatotakada Municipal Hospital , 1-1, Isono-Cho, Yamatotakada-Shi, Nara-Ken , Japan
1 Department of Cardiovascular Surgery, Nara Medical University , 840, Shijo-Cho, Kashihara-Shi, Nara-Ken , Japan
2 Department of Surgery, Yamatotakada Municipal Hospital , 1-1, Isono-Cho, Yamatotakada-Shi, Nara-Ken , Japan
Background: Left atrial thrombi have traditionally been treated with heparin and warfarin, and many physicians have limited experience with direct oral anticoagulants such as apixaban. Furthermore, the efficacy of apixaban for the treatment of left atrial thrombi has not been established. We experienced a case of left atrial thrombus formation before breast cancer surgery, which was resolved by apixaban. Case presentation: Computed tomography for a 74-year-old Japanese woman with breast cancer incidentally revealed a left atrial mass with a root before the breast surgery. The mass was surgically removed and determined to be a thrombus. Before the breast surgery, transthoracic echocardiography was performed again, and the left atrial thrombus had recurred within only 14 days. It resolved after administration of apixaban. Conclusions: A left atrial thrombus might recur within a very short time. Apixaban might be an alternative to warfarin in patients with breast cancer and left atrial thrombus.
Apixaban; Thrombus; Left atrial mass
Left atrial thrombus is one of the differential diagnoses
of a left atrial mass and is usually observed in the left
atrial appendage. Historically, left atrial thrombi have
been treated with heparin and warfarin. Recently, direct
oral anticoagulants (DOACs) have been developed, and
the superiority of DOACs to warfarin in preventing
stroke and reducing bleeding has been demonstrated
. However, the efficacy of a DOAC such as apixaban
for the treatment of left atrial thrombus has not been
established. We experienced a case of a left atrial mass
in a patient with breast cancer. The mass was a thrombus
that recurred in only 14 days and then resolved
completely after approximately 2 months of apixaban
A 74-year-old Japanese woman (height 136 cm; weight
40 kg) without systemic disease presented to our
hospital with a palpable 15-mm mass in her left breast that
was identified as stage I breast cancer. Before surgery for
removal of the mass, a contrast-enhanced pulmonary
computed tomography (CT) was performed and showed
a mass approximately 30 × 30 mm in her left atrium
Based on transthoracic echocardiography (TTE), her
left ventricle ejection fraction was 65.3 % and her left
atrial diameter was 42 mm; the mass was 33 × 30 mm, it
had a root, it was located on the surface of the septal
wall, and was oscillating (Fig. 2). An electrocardiogram
showed paroxysmal atrial fibrillation. Her chest
radiography was normal. Her CHA2DS2-VASc score was
2, CHADS2 score was 0, and HAS-BLED score was 1.
Laboratory investigations revealed the following:
hemoglobin level, 12.8 g/dL; serum creatinine level,
0.67 mg/dL; estimated glomerular filtration rate,
64.6 mL/minute/1.73 m2; brain natriuretic peptide,
199.2 pg/dL; international normalized ratio (INR),
1.04; activated partial thromboplastin time (APTT),
32.5 seconds; protein C, 113 %; protein S, 75 %;
antinuclear antigen, 40; and lupus anticoagulant, 1.4 seconds.
Her levels of cancer antigen 15-3 and NCC-ST 439 were
23.8 U/mL and 1.3 U/mL, respectively.
Cardiac surgery was performed 16 days after her first
visit to remove the left atrial mass. On pathologic
examination, the mass consisted of a thrombus, without
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Fig. 1 A 30 × 30-mm mass in the left atrium on contrast-enhanced
computed tomography of the chest (black arrow)
Fig. 2 Transthoracic echocardiography showing a 33 × 30-mm mass
in the left atrium (white arrow)
Fig. 4 Fourteen days after cardiac surgery, a thrombus had formed
over the lateral left atrium wall (white arrow)
tumor cells (Fig. 3). After removal of the left atrial
mass, heparin was initiated, and breast surgery was
Fourteen days after her cardiac surgery, TTE was
performed, showing a mass formation in the lateral wall of
her left atrium (Fig. 4). The mass was 38 × 31 mm and
was potentially a thrombus. Therefore, her breast
operation was postponed and 1 mg/day of letrozole was
administered to prevent progression of the breast cancer.
The left atrial thrombus was treated with heparin and
warfarin. Because her INR level fluctuated, rivaroxaban
was administered. However, owing to gastrointestinal
upset, she did not take rivaroxaban; therefore, 5 mg of
apixaban twice a day was prescribed. Approximately
2 months later, TTE and contrast-enhanced pulmonary
Fig. 3 Left atrial mass pathology showing the mass was composed of a thrombus, without tumor tissue
Fig. 5 The cardiac thrombus disappeared on transthoracic echocardiography and contrast-enhanced computed tomography of the chest
CT showed resolution of the left atrial thrombus (Fig. 5).
After complete resolution of the left atrial thrombus, her
breast surgery was performed. During the
anticoagulation therapy, thromboembolism and lethal hemorrhage
did not occur.
This case highlighted three important clinical issues.
First, apixaban effectively resolved the left atrial
thrombus. DOACs such as apixaban have recently been
developed and are superior to warfarin for preventing
stroke and reducing bleeding . Although there have
been some case reports of resolution of a left atrial
thrombus with apixaban [2–4], the mechanisms of
thrombus resolution are not fully understood. One
possible mechanism is that antithrombin is not required
for the antithrombotic activity of apixaban, which is a
selective factor Xa inhibitor. It inhibits both free and
clot-bound factor Xa as well as prothrombinase activity.
It indirectly inhibits platelet aggregation and decreases
thrombin generation and fibrin clot development [5, 6].
In addition, the fibrinolytic system plays a role in
thrombus resolution. Because of the limited experience
with DOACs for left atrial thrombus resolution,
additional cases and further investigation are needed to
establish the efficacy of apixaban for this purpose.
Second, the cardiac thrombus relapsed in a very short
time after removal. Our patient had paroxysmal atrial
fibrillation and cancer. Malignancy has a significant
role in a thrombus, and venous and arterial
thromboembolisms are common complications for patients with
cancer . In a normal coagulation-fibrinolysis system,
there is a natural balance between activation and
inhibition of procoagulants and anticoagulants. Cancer cells
can alter this balance through the production of
cancer-related procoagulants such as tissue factor and
cancer procoagulant . Tissue factor is a
transmembrane glycoprotein and the primer of the physiological
coagulation cascade. Cancer procoagulant, a cysteine
protease, is a direct activator of factor X and is found
in malignant tissues. Cancer procoagulant, in the presence
of factor V, enhances thrombin production .
Tumorspecific activation of factor X might be an important step
in the blood coagulation cascade in patients with cancer.
In our case, we used a direct Xa inhibitor (apixaban),
which resulted in a favorable outcome.
Finally, differential diagnoses of intracardiac mass are
a benign tumor, malignant tumor, metastatic tumor, and
thrombus. Atrial myxoma is the most common primary
intracardiac tumor in adults; two thirds of myxomas
arise in the left atrium . However, cardiac thrombi
typically occur in the left atrial appendage. In the
present case, the left atrial mass had a root and
oscillated, which are typical characteristics of myxomas and
atypical characteristics of a left atrial thrombus.
The authors would like to thank Dr Tokiko Nakai (Nara Medical University,
Department of Pathology, Kashihara, Japan) who performed the histological
examination of the left atrial mass. We would also like to thank Ms Yuki
Tsutsumino (Yamatotakada Municipal Hospital) who performed cardiac
ultrasonography on multiple occasions. We would like to thank Editage
(www.editage.jp) for English language editing.
Availability of data and materials
All data and materials described in this manuscript are fully anonymous.
RO first found the left atrial mass and performed breast surgery. ST performed
cardiac surgery. All authors read and approved the final manuscript.
Consent for publication
Written informed consent was obtained from the patient for publication of
this case report and accompanying images. A copy of the written consent
form is available for review by the Editor-in-Chief of this journal.
Ethics approval and consent to participate
This study has been performed in accordance with the Declaration of Helsinki
and has been approved by ethics committee of Yamatotakada Municipal
Hospital. The committee’s reference number is H28-4.
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