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.