Asian Cardiovasc Thorac Ann 2006;14:425-427
© 2006 Asia Publishing EXchange Ltd
Malignant Peripheral Nerve Sheath Tumor of the Heart
Mesbah Rahman, FRCS,
Deborah S Cook, MRCPath1,
Gethin Ellis, MRCP2,
Peter A O’Keefe, FRCS1
Department of Cardiothoracic Surgery
1 Department of Pathology, University Hospital Wales, Cardiff
2 Department of Cardiology, Royal Glamorgan Hospital, Llantrisant, United Kingdom
For reprint information contact: Mesbah Rahman, FRCS Tel: 44 179 270 2222 ext 3608 Fax: 44 179 270 4159 Email: mesbah{at}hotmail.com, Cardiac Surgery, Morriston Hospital, Swansea, SA6 6NL, United Kingdom
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ABSTRACT
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A 32-year-old man presented with dyspnea, chest pain, palpitations and ankle edema and was found to have a tumor involving the heart. This was diagnosed as malignant peripheral nerve sheath tumor, a rare sarcoma of the heart. Immunohistochemistry was utilized to establish the diagnosis. The details of the patient’s clinical course, and imaging findings with morphological and immunohistochemistry data are reported.
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INTRODUCTION
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Primary malignancy of the heart is rare. The incidence of primary cardiac tumors ranges from 0.001 – 0.03%.1 Approximately 75% of cardiac tumors are benign, of which myxoma is the most common. The remaining 25% are malignant and nearly all of them are sarcomas. Among the primary cardiac tumors, malignant peripheral nerve sheath tumor (MPNST) of the heart is exceedingly rare.1 We discuss a patient with primary MPNST of the heart together with a literature review of cardiac sarcomas.
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CASE REPORT
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A 32-year-old male with no significant past medical history presented with a 9 month history of gradual onset of exertional dyspnea, chest pain and weight loss. His chest pain was a dull ache in nature and located retrosternally with no aggravating or relieving factors. He had started to experience paroxysmal palpitations and ankle edema but denied any orthopnea or paroxysmal nocturnal dyspnea. Clinical examination revealed signs of superior vena cava (SVC) obstruction and congestive cardiac failure. The area of cardiac dullness was expanded. There were no stigmata of neurofibromatosis Type 1.
Chest X-Ray showed bilateral pleural effusions, cardiomegaly and an oligemic right lung field. Electrocardiogram (EKG) was low voltage. Transthoracic echocardiography (TTE) demonstrated significant pericardial effusion; 800 mL of a blood-stained fluid was subsequently drained percutaneously. Post drainage TTE revealed a large soft tissue mass appearing to encircle the heart and compressing both atria. Computerized tomography (CT) scan of the thorax (Figure 1
) and abdomen confirmed a large left pleural effusion with complete collapse of the left lung. There was a large soft tissue mass within the pericardium but no intra-cavity cardiac mass. No metastasis was evident. Magnetic resonance imaging (MRI) of the heart (Figure 2) identified a large mass, predominantly solid with some cystic components, within the pericardium. The SVC and the right pulmonary artery were virtually occluded extrinsically. No disease was seen outside the pericardium. The great vessels were free of tumor and there was no transluminal tumor propagation.
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Figure 1. CT scan of the chest; tumor mass surrounding the heart contained within the pericardium. Note large left pleural effusion and collapsed lung. RA: right atrium; RV: right ventricle; LV: left ventricle.
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Figure 2. MRI scan of the heart showing large mass in the superior mediastinum surrounding the great vessels; right pulmonary artery (P) is compressed. Superior vena cava (S) is stented.
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The SVC was stented and a left anterior thoracotomy performed. The pericardium was engorged but completely free from the heart. The left phrenic and vagus nerve were identified and free from tumor involvement. An irregular shaped soft yellowish friable tumor mass was attached to the anterolateral wall of the heart and filled the pericardial recesses. No other structure apart from the heart was involved by the tumor mass. It was deemed unresectable and biopsies were taken for histology.
Microscopic examination (Figure 3) showed solid sheets of small tightly packed spindle cells with inconspicuous cytoplasm and ovoid nuclei without significant pleomorphism. Mitotic activity was high with foci of necrosis. Cells were negative for AE1/AE3, CEA, vimentin, desmin, smooth muscle actin, myoglobin and CD5. CD57 and S100 staining was focally positive. Cytogenetics was not performed. This histological picture was in keeping with malignant peripheral nerve sheath tumor (MPNST). The patient deteriorated rapidly and died of rapid progression of the tumor despite chemotherapy and radiotherapy. Permission for autopsy was denied by the relatives.
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Figure 3. Photomicrograph showing malignant spindle cell tumor with frequent mitosis (hematoxylin and eosin stained; original magnification x 100).
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DISCUSSION
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Malignant peripheral nerve sheath tumor of the heart is exceedingly rare and comprises only 0.75% of all cardiac tumors.2 Previously MPNST was also known as malignant schwannoma, neurofibrosarcoma and neurogenic sarcoma.3 As a result of differences in nomenclature in the past, and lack of standard diagnostic criteria, it is difficult to assess the exact number of similar cases reported. It occurs more commonly in extremities in association with major nerve trunks, but in cardiac cases it originates from the cardiac plexus, and from branches of the vagus or phrenic nerves.2 Symptoms do not develop until the tumor interferes with cardiac function. Dyspnea, fatigue, fever, cough, chest pain, anorexia, weight loss, arrhythmia and peripheral embolism have been reported.1,2,4–6 Clinical signs depend on location and extent of involvement.4 Cardiac dullness is expanded usually due to pericardial effusion. Signs of superior vena cava obstruction and congestive cardiac failure are often present.2 Electrocardiogram may be entirely normal.6 Heart block, arrhythmia and ST-T wave changes indicate myocardial invasion and damage.2,6 Chest X-Ray findings may be normal but more usually cardiomegaly, abnormalities of cardiac contour, pleural effusion and signs of heart failure are evident.4
Diagnosis is greatly facilitated by echocardiography which can detect pericardial effusion, tumor location and any hemodynamic consequences.4 A large pericardial effusion may obscure the tumor and drainage facilitates the detection by echocardiography.1 Transesophageal echocardiography is frequently used for a more comprehensive study of the tumor.4,6 Computerized tomography scan demonstrates the location and extent of the tumor including details of pericardium, great vessels, and metastases.4 The wide field of view, high contrast, spatial resolution and multiplanar capabilities allow MRI to localize the tumor precisely, including its relationship with cardiac chambers, contiguous structures, and myocardial involvement.4 Magnetic resonance imaging is especially important in determining the resectability and surgical approach.
Histologically, MPNST presents a variety of appearances; the majority show fascicular spindle cell architecture, but there may also be myxoid areas and perivascular whirling.7 Necrosis and mitotic activity are common, reflecting the high-grade nature of the majority of these tumors. Malignant peripheral nerve sheath tumor may be indistinguishable from other sarcomas on routine hematoxylin and eosin staining, and immunocytochemistry is important for diagnosis. Approximately 50% of MPNST are positive for S100, although the positivity may be patchy. Other neural markers, such as CD57 (Leu-7), and GFAP are useful as second-line markers. The tumor should be negative with specific markers for other sarcoma lineages.7 The diagnosis in this case was made by a combination of routine histochemistry and the appropriate immunochemistry. Although not performed in this case, cytogenetics of the tumor can be useful in reaching the correct diagnosis.
Malignant peripheral nerve sheath tumor of the heart is a highly aggressive tumor with uniform fatality. Due to its rarity, general strategies for management and prognosis of such tumors are unclear. Like sarcomas in any location, resection should be the procedure of choice. All reported series on cardiac sarcomas claimed improved survival for complete resection.5,6 Even incomplete excision offers better palliation.5 The effect of adjuvant chemotherapy and radiotherapy is difficult to judge because of the small number of cases in any series. However, most authors claim no survival benefit for adjuvant therapy.5,6 Local recurrence is common even after complete excision of the tumor.5 Median survival ranges from 3 months to 1 year and prognosis correlates with histological grading but not histological type.4,5,6
Allogenic heart transplantation or bench surgery, to facilitate complete excision of the tumor, with auto transplantation has been tried with some success5,8 and may be the only surgical option to treat such an aggressive tumor in a highly sensitive location.
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REFERENCES
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- Burke AP, Virmani R. Tumors of the heart and great vessels. In Atlas of Tumour Pathology, 3rd series, fasc 16, Washington, DC. Armed Forces Institute of Pathology, 1996, pp 1–11.
- Morishita T, Yamazaki J, Ohsawa H, Uchi T, Kawamura Y, Okuzumi K, et al. Malignant schwannoma of the heart. Clin Cardiol 1988;11:126–30.[Medline]
- Weiss SW, Goldblum JR, Malignant tumor of the peripheral nerves, In Soft tissue tumors, 4th edition. Mosby, St Louis, 2001:1209–331.
- Grebenc M L, Rosado de Christenson ML, Burke AP, Green CE, Galvin JR. Primary cardiac and pericardial neoplasms: radiologic-pathologic correlation. Radiographics 2000;20:1073–103.[Abstract/Free Full Text]
- Putnam JB Jr, Sweeney MS, Colon R, Lanza LA, Frazier OH, Cooley DA. Primary cardiac sarcomas. Ann Thorac Surg 1991;51:906–10.[Abstract]
- Burke AP, Cowan D, Virmani R. Primary sarcomas of the heart. Cancer 1992;69:387–95.[Medline]
- Fletcher CDM. Peripheral neuroectodermal tumors. In Fletcher CDM (Editor): Diagnostic histopathology of tumors. Volume 2 (2nd edition).London: Churchill Livingstone, 2000:1679–711.
- Reardon MJ, DeFelice CA, Sheinbaum R, Baldwin JC. Cardiac autotransplant for surgical treatment of a malignant neoplasm. Ann thorac surg 1999;67:1793–5.[Abstract/Free Full Text]
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ABSTRACT
INTRODUCTION
