Unusual CT features of primary cardiac metastatic angiosarcoma

Clinical History

A 20-year-old woman presented in the emergency department with dyspnoea and chest pain that have become more persistent and severe in the last 2 months. Her physical examination was unremarkable, as was cardiac and lung auscultation. The body temperature was sub-febrile, the blood tests did not show any significant alterations.

Imaging Findings

The echocardiography showed moderate pericardial effusion that impaired an accurate evaluation of the heart's morphology. The patient was admitted into our institution for aetiological evaluation and, on the first day of her stay, the chest radiography showed bilateral pneumothoraces after one episode of hemoptysis. The pneumothoraces were drained and she also underwent a pericardiocentesis for cardiac tamponade that she developed concurrently. The CT showed an anterior mediastinal mass with irregular borders (Fig. 1), in close proximity with the right atrium—its free border was not depicted (Fig. 2). This mass had an avid and homogeneous enhancement, with the same densities as the blood pool within the heart, making it difficult to distinguish from the right atrium (Fig. 2). Mediastinal lymphadenopathies (Fig. 3) and multiple lung nodules, many in a sub-pleural location (Fig. 4), were also described and suggested disseminated malignant disease.

Discussion

Primary cardiac tumours are extremely rare, with a cumulative prevalence of 0.002%-0.3%, with metastatic involvement of the heart being 30 times more prevalent [1]. Most primary heart tumours are benign and only 25% are malignant—of these 95% are cardiac sarcomas [2]. There are many sub-types of cardiac sarcomas—angiosarcoma is the most frequent in adults and other sub-types include rhabdomyosarcoma, pleomorphic undifferentiated sarcoma, and fibrosarcoma [3]. Angiosarcomas are malignant mesenchymal tumours that usually affect patients younger than 65 years old with a male to female ratio of 3:1 [1, 2, 4]. They originate non-specific symptoms like malaise, anaemia or chest pain, with dyspnea being the commonest [2, 4]. Angiosarcomas are generally found in the right atrium, have aggressive and permeating growth and usually invade the pericardium, leading to pericardial effusion, with or without cardiac tamponade—physicians should consider this rare disease in the differential diagnosis of a young patient with recurrent pericardial effusions of unknown aetiology [1-4]. They are usually disseminated at presentation, particularly to the lung—other common sites include the liver, lymph nodes, bone and adrenals [1, 2, 4].
At chest radiography cardiomegaly is the most common finding [3]. Echocardiography is a cheap screening modality that is widely available and can show the tumour's location and size, as well as whether cardiac function is compromised [4, 5]. Cardiac angiosarcomas are ill-defined, in-homogeneous, large, hyper-echoic masses that invade adjacent structures [4]. CT is an important imaging tool to assess resectability and systemic metastasis, without the motion artifacts related to magnetic resonance imaging (MRI), and can even guide a transthoracic biopsy [2, 4]. It usually shows a low-attenuated right atrial mass, that can either be irregular or nodular, with nodular and inhomogeneous enhancement [1, 3, 5]. Cardiac MRI is superior to CT for soft tissue characterisation—cardiac angiosarcomas have a papillary appearance with heterogenous signal intensity at T1-weighted images and high signal intensity at T2-weighted images [1, 4].
Only an early diagnosis can prevent tumour progression and metastasis, but unfortunately cardiac angiosarcomas are usually delayed and their prognosis is poor - 2.5 to 30 months after the diagnosis [2-4]. Given its low incidence there aren’t any standard treatment guidelines, with the treatment being different therapeutical combinations between surgery, chemotherapy, radiation and/or transplantation [2, 4, 5].

Differential Diagnosis List

Final Diagnosis

Primary cardiac metastatic angiosarcoma

URL:	https://eurorad.org/case/14400
DOI:	10.1594/EURORAD/CASE.14400
ISSN:	1563-4086