Abstract

We present a very rare case of high-grade intimal sarcoma/cardiac pleomorphic sarcoma that was metastatic to the small bowel and presented with small bowel obstruction. Surgical resection was successfully performed of the intussuscepted portion of the small bowel segment followed by resection of the left atrial mass. The patient tolerated the procedure very well and is currently undergoing chemotherapy with doxorubicin/ifosfamide.

1. Introduction

A 67 years old female presented to clinic with one week history of severe, sudden-onset, sharp, intermittent right lower abdomen pain that radiated to the back with associated diarrhea, chills and abdominal bloating. subsequently, the patient was admitted to the hospital for further evaluation. On initial evaluation, blood pressure 130/74, heart rate 73, temperature 99 F, SpO2 98%. Physical examination notable for epigastric tenderness to deep palpation. There was no evidence of distension, rigidity, or guarding. Cardiac examination was normal with regular rate and rhythm with no evidence of murmur, gallop, or rub.

2. Past Medical History

This patient had prior diagnoses of hypertension, hyperlipidemia, hyperthyroidism with history of thyrotoxicosis with diffuse goiter, and remote tobacco use (<1/4 PPD for 5 years; quit 30 years prior).

3. Investigations

Blood studies revealed microcytic anemia (hemoglobin 9.0)with decreased iron and percent transferrin saturation consistent with iron deficiency anemia. Comprehensive metabolic panel was unremarkable with normal liver function tests. Cardiac troponin was less than 0.01. The initial EKG revealed normal sinus rhythm with no ST or T wave abnormalities. A CT of the abdomen and pelvis with IV and oral contrast was notable for enteroenteric intussuption with ileus of the small bowel, as well as an incidental 2.3 cm x 3.0 cm x 2.6 cm filling defect in the cardiac left atrium (Figure 1). Transthoracic echocardiogram (TTE) performed on same day of CT scan also demonstrated an echodense structure located in the left atrium, measuring 2.0 cm x 2.9 cm (Figure 2 and Video 1). For further evaluation, transesophageal echocardiogram (TEE) further characterized the mass as 2.0 cm x 2.0 cm mobile echodensity attached to the interatrial septum in the left atrium as well as a possible second smaller 1.5 cm x 0.8 cm mass posterior to the first mass, also attached to the interatrial septum (Figure 3 A and B). Subsequently, the patient underwent laparoscopic resection of the small bowel mass, which was sent for microscopic evaluation (Figure 4 A and B). The pathology of the mass revealed high-grade sarcoma, most compatible with metastasis from an intimal sarcoma/pleomorphic sarcoma.

To further evaluation the left atrial mass, cardiac MRI was obtained. It showed normal left ventricular systolic function and a left atrial mass attached to the mid-atrial septum with no definite stalk visualized. The mass appeared to have two lobes and measured 3.9 cm x 2.3 cm and did not enhance (Figure 5). She underwent cardiac PET that showed minimal uptake of FDG in the atrial mass with SUV 4.1 and no other sites of disease. She underwent incomplete resection of the mass along with incomplete resection of a second mass located at the roof of the left atrium approximately 2 months after initial CT scan (Figure 6 and Videos 2 and 3). Full resection of the intra-cardiac mass was felt to be impossible with clear margins and therefore biopsies were taken. Pathology evaluation identified a grade 3, 4 cm intimal sarcoma/cardiac pleomorphic sarcoma. One of the resected nodules was sarcoma and another was dense fibrous tissue. Cytogenetics identified MDM2 amplification. The small bowel mass was re-evaluated and had MDM2 amplification and similar appearance to the cardiac mass. The diagnosis was revised to metastatic intimal sarcoma/cardiac pleomorphic sarcoma.

4. Differential Diagnosis

The initial differential diagnosis included benign and malignant cardiac tumors. Given the location of the mass in the left atrium, the size of the mass, and increased prevalence of benign versus malignant tumors, the mass was initially thought to be a myxoma. Other leading differentials included other types of cardiac tumors, including lipoma and malignant primary tumors, such as sarcomas. Given the metastasizing mass with intussuption noted on initial imaging, metastatic sarcoma was the leading differential diagnosis, which was confirmed with cytology.

5. Management (medical/interventions)

After diagnosis of intussusception with ileus, the initial management was emergent laparoscopic surgery with resection of intussuscepted portion of the small bowel segment (Figure 3). After bowel resection, patient had extensive imaging of intracardiac mass with transthoracic echocardiogram, transesophageal echocardiogram, cardiac MRI with and without gadolinium, and cardiac PET. She underwent incomplete resection of the cardiac masses. As noted above, pathology confirmed metastatic intimal sarcoma/cardiac pleomorphic sarcoma. Given incomplete resection of cardiac mass, patient was started on chemotherapy with doxorubicin/ifosfamide.

6. Discussion: Association with current guidelines / position papers / current practice

Primary cardiac tumors are extremely rare, with a reported prevalence between 0.0017% and 0.028%. ¹ Approximately 25% of all primary heart and pericardial tumors are malignant. ^{2, 3} Of the primary cardiac malignancies, the majority are sarcomas, with a heterogenous group of histologies. ^{4, 5} Of the sarcomatous tumors, the most common histological types are leiomyosarcoma, osteosarcoma, rhabdomyosarcoma, fibrosarcoma or synovial sarcoma. ⁵ Cardiac intimal sarcoma is a poorly differentiated mesenchymal tumor which occurs mainly in the large blood vessels, such as the aorta and pulmonary artery, and rarely in the heart. ⁵ It is the least frequent cardiac sarcoma. ⁵ However, a 2014 retrospective analysis by Neuville et al, demonstrated that cardiac intimal sarcomas were the most frequently diagnosed primary cardiac sarcoma at 42%. This was followed by angiosarcoma at 26%, undifferentiated sarcoma at 22%, synovial sarcomas at 7%, leiomyosarcomas at 2%, and peripheral neuroectodermal tumors at 1%. ⁶ Additionally, MDM2 over-expression is known to be a characteristic genetic finding that supports the diagnosis of intimal sarcoma. ⁶

Presentation of cardiac malignancies typically occur after a long period of clinical silence. ⁷ Symptoms vary based on tumor location, size, invasiveness, friability, and rate of growth. ⁴ Symptoms can include obstructive symptoms; arrhythmias, if the tumor is located near conduction tissue; embolization; or myocardial or pericardial infiltration. ^{4, 5} Compared to other malignant cardiac tumors, cardiac sarcomas have poorer outcomes due to rapid progression of size, infiltration of the myocardium, obstruction of circulation, and high likelihood of metastatic disease. ^{4, 8}

Treatment options are limited to surgical resection for primary cardiac tumors and chemotherapy for metastatic disease. Surgical resection with negative margins is important in preventing local recurrence and improvement in survival. ⁹ A recent study by Sultan et al., which evaluated operative and long-term survival outcomes for primary malignant cardiac tumors, performed a retrospective analysis of 100,317 tumors, of which 826 were primary malignant tumors. After exclusion criteria, the cohort consisted of 747 patients, of which 99.5% were diagnosed with primary sarcomas. They found that surgery in comparison to no surgery had significantly better long-term survival (p<0.0001). For patients with Stage III disease, there was a statistically significant improvement in survival with addition of chemotherapy to surgery. The greatest risk factors for mortality were advanced age, higher co-morbidity index, hemangiosarcoma history and presence of metastases. ¹⁰

7. Follow-up

The patient was followed up as an outpatient in the oncology and cardiology clinics. One month after resection of intracardiac mass, repeat TTE did not show any evidence of the mass in left atrium, but noted thickened interatrial septum compatible with recent septal patching. Global longitudinal strain (GLS) was assessed prior to initiation of chemotherapy and it was measured at -17% (Figure 7). Two months after incomplete resection of intracardiac mass, patient is currently on undergoing chemotherapy with doxorubicin/ifosfamide. Repeat cardiac MRI revealed after surgerical resection and three cycles of chemotherapy did not demonstrate any mass in the left atrium. The mass appeared to be completed resected.

8. Conclusions

This case highlights the incidental finding of cardiac sarcoma, extensive imaging, and management associated with primary cardiac sarcoma with metastasis to the small intestine. Early recognition is important for early surgical resection and improvement in morbidity/mortality.

ACKNOWLEDGEMENTS

The authors thank the patient, her family, and the staff working at Corewell Health East-Dearborn.

Abbreviations

PPD, pack per day; EKG, electrocardiogram; CT, computed tomography; TTE, transthoracic echocardiogram; TEE, transesophageal echocardiogram; MRI, magnetic resonance imaging; PET, positron emission tomography; FDG, F-fluorodeoxyglucose: SUV, standardized uptake value; MDM2, murine double minute-2; GLS, global longitudinal strain.

References