Malignant Tumours of the Heart: A Review of Tumour Type, Diagnosis and Therapy

Abstract

Primary cardiac neoplasms are rare and occur less commonly than metastatic disease of the heart. In this overview, current published studies concerning malignant neoplasms of the heart are reviewed, together with some insights into their aetiology, diagnosis and management. We searched medline using the subject ‘cardiac neoplasms’. We selected about 110 articles from between 1973 and 2006, of which 76 sources were used to complete the review. Sarcomas are the most common cardiac tumours and include myxosarcoma, liposarcoma, angiosarcoma, fibrosarcoma, leiomyosarcoma, osteosarcoma, synovial sarcoma, rhabdomyosarcoma, neurofibrosarcoma, malignant fibrous histiocytoma and undifferentiated sarcoma. The classic symptoms of cardiac tumours are intracardiac obstruction, signs of systemic embolisation, and systemic or constitutional symptoms. However, serious complications including stroke, myocardial infarction and even sudden death from arrhythmia may be the first signs of a tumour. Echocardiography and angiography are essential diagnostic tools for evaluating cardiac neoplasms. Computed tomography and magnetic resonance imaging studies have improved the diagnostic approach in recent decades. Successful treatment for benign cardiac tumours is usually achieved by surgical resection. Unfortunately, resection of the tumour is not always feasible. The prognosis after surgery is usually excellent in the case of benign tumours, but the prognosis of malignant tumours remains dismal. In conclusion, there are limited published data concerning cardiac neoplasms. Therefore, a high level of suspicion is required for early diagnosis. Surgery is the cornerstone of therapy. However, a multi-treatment approach, including chemotherapy, radiation as well as evolving approaches such as gene therapy, might provide a better palliative and curative result.

Introduction

The first heart tumours were described by Colomnus in the 15th century and by Boneti in the 18th century. Alberts documented for the first time in 1835 resection of a cardiac tumour. The invention of cardiopulmonary bypass in 1955 brought major changes and improvements to the management of heart tumours. Primary tumours of the heart, with the exception of atrial myxomas, are very rare (a prevalence of 0.001–0.28%) [1]; metastases to or direct invasion of the heart are far more common. About 75% of primary heart tumours are benign, and 75% of those are atrial myxomas [2]. The remaining 25% of cardiac tumours are malignant, 75% of them being sarcomas. Sarcomas are the largest group of primary cardiac malignant neoplasms and have a mesenchymal origin. Soft tissue sarcoma is the most common malignant tumour of the heart, pericardium, and great vessels. It is a rare tumour and its presentation is non-specific and subtle 2, 3. A review of 12 485 autopsies revealed only seven cases of primary neoplasm of the heart, whereas the investigators found 154 cases of metastatic heart tumours [4]. The most common cardiac sarcomas are angiosarcomas, rhabdomyosarcomas, malignant mesotheliomas and fibrosarcomas 1, 2. Table 1 illustrates the most common malignant sarcomas of the heart [1].

Angiosarcoma is the most frequent type of sarcoma in the adult population, and occurs more frequently in males [1]. Because of their exposure in the circulation, metastases are common and widespread. Signs and symptoms of these tumours are non-specific, which makes early diagnosis more challenging [4]. The subtypes of primary cardiac sarcoma include angiosarcoma, rhabdomyosarcoma, fibrosarcoma, malignant schwannoma and osteosarcoma 4, 5, 6. Burke et al.[7] reported that in a large series (n = 75) of primary cardiac sarcomas, angiosarcomas are the most common cardiac sarcomas and are predominantly right sided, whereas osteosarcomas are more frequently left sided. Right atrial lesions are more frequently malignant (usually angiosarcomas). Left-sided atrial lesions are usually myxomas. However, if malignant, they are often malignant fibrous histiocytomas (MFH) [8]. Rhabdomyomas are the most frequent cardiac neoplasms in the paediatric population, followed by fibromas and teratomas [9].

Several autosomal dominant familial conditions that combine lentiginosis and cardiac myxomas have been described. The Carney complex describes the lentigines, atrial myxomas, mucocutaneous myxomas and blue nevi (LAMB) and nevi, atrial myxoma, myxoid neurofibroma and ephelides (NAME) syndrome. The Carney complex is inherited as an autosomal dominant trait and accounts for 7% of all cardiac myxomas. Carney complex findings include cardiac myxomas, cutaneous myxomas, pigmentation of the skin, and both endocrine and non-endocrine tumours. Cardiac myxomas are thought to arise from primitive subendocardial mesenchymal multipotent precursor cells [10]. The Carney complex is associated with a mutation in the gene MYH8, which encodes for the perinatal myosin heavy chain 11, 12.