Outcome and Follow-up
Due to the widespread local disease, complete excision of the mass was
not possible. Patient was discharged on metoprolol succinate 25 mg and
amiodarone 200 mg daily and was scheduled to follow up with oncology and
cardiology.
Discussion
Primary Cardiac tumors are extremely rare. Comparatively, metastatic
cardiac tumors are far more common than primary cardiac
tumors.1 Sarcomas are malignant tumors that are of
mesenchymal origin, comprising less than 1 percent of malignancies in
adult.2 Liposarcomas are malignancies of soft tissue
and have been described into three main subtypes:
well-differentiated/dedifferentiated, myxoid/round cell, and
pleomorphic.3 The myxoid liposarcoma is the second
most common subtype of liposarcoma and account for approximately 10% of
all adult soft tissue sarcomas.3,4,5
Myxoid liposarcoma is the second most common subtype of liposarcoma. It
is characterized by a recurrent translocation (12;16)(q13;p11) that
results in FUS-CHOP gene fusion, which occurs in more than 95% of
cases. In other rare cases, a similar variant has been characterized
(12;22)(q13;q12) which fuses EWSR1 to DDIT 3. These translocations are
believed to be the primary oncogenic event stimulating the proliferation
of tumor cells of myxoid liposarcoma.3 Myxoid
liposarcomas can arise in any part of the body but have a propensity to
occur in the lower extremities and buttocks. They have a peak incidence
in patients in their fourth and fifth decades of
life.6,7 Myxoid liposarcoma also known to have unusual
metastasize to extrapulmonary sites such as retroperitoneum,
intra-abdominal cavity, and bone.5,6,7
Aforementioned case describes the primary tumor for the patient was
found in right thigh. Myxoid liposarcoma is also known to have unusual
metastasize extrapulmonary sites such as the retroperitoneum,
intra-abdominal cavity, and bone.5,6,7 Cardiac
metastases of myxoid liposarcoma are extremely rare, with approximately
thirty cases reported previously.9 The time interval
between the primary lesion and cardiac metastasis is relatively long,
ranging from 1 to 25 years.8,9 Our patient’s primary
tumor presented in 2007, and the cardiac metastasis presented 15 years
after the onset of primary tumor.
The symptoms of cardiac tumors are determined by the location of the
tumor in the heart. Only 10% of patients with cardiac metastasis have
been reported symptoms.10, 12 Left ventricle tumors in
particular may present with arrhythmias or conduction defects. If
intracavitary, the tumor can cause outflow obstruction, syncope, and
left ventricular failure.12 Our patient presented with
cardiac arrhythmia and symptoms of frequent palpitations.
Furthermore, the diagnostic workup for secondary cardiac tumors is
generally aimed to ascertain whether or not cardiac tumor is present.
Patients with a known history of malignancy that manifest a change in
their clinical status associated with arrythmias or murmurs may warrant
further investigations.12 TTE and cardiac MRI was used
in our case as part of the initial investigation and diagnosis. These
imaging studies provided critical information regarding location, tumor
homogeneity and relation to surrounding structures. As cardiac
metastases generally represent widespread disease, FDG-PET/CT was also
used in the staging workup of liposarcoma to detect distant metastases.
The treatment of cardiac metastasis is very challenging. Surgery is an
option, and it has been shown to improve symptom palliation and prolong
life.11 However, in our patient, because the
widespread local disease, the tumor was not amenable to resection. The
adjuvant chemotherapy and radiotherapy for secondary cardiac tumor are
avenues still in need of further investigation.
Little in-depth investigation exists at this time regarding cardiac
metastasis. This is in part due to the rarity of the cases. Currently
there is a lack of screening regimens, and targeted therapy for sarcoma
and cardiac metastases has not been rigorously studied. However, because
of the severity of the conditions and the high potential for morbidity
and mortality associated with these lesions, we hope to contribute data
to allow further investigation into targeted screening of cardiac
metastasis leading to earlier diagnosis, treatment and hopefully a
better outcome.