The lingering mysteries of metastatic angiosarcoma: A rare case report

A 45-year-old male patient presented to the emergency department with a history of chest pain and haemoptysis for one month. On examination, his vitals were stable, and other systemic examinations were unremarkable. Sputum evaluation for Acid-Fast Bacilli (AFB) and gene expert were negative. Haematological investigations showed a rise in erythrocyte sedimentation rate measuring 30 mm/hr (normal ≤ 15 mm/hr) and C-reactive protein levels of 24 mg/dL (normal <0.3 mg/dL). Electrocardiography was normal.

The CT chest revealed numerous variable-sized soft tissue density nodules scattered throughout the lung parenchyma in random distribution (Figures 1a and 1b), with surrounding ground glass densities giving the appearance of a “halo sign” (Figure 1a, arrowhead).

On contrast imaging, the nodules show significant arterial and venous phase enhancement, suggesting haemorrhagic metastasis (Figure 2b).

The right atrium appeared enlarged in size with irregular wall thickening. There was abnormal enhancement of the right atrial appendage, lateral and posterior wall of the right atrium extending up to the tricuspid valve (Figure 3a), and peripherally it was seen obliterating the pericardial fat pad with invasion into the pericardial lining (Figure 3b).

Later Fluorodeoxyglucose (FDG) – Positron Emission Tomography (PET) imaging, the right atrial lesion showed intensely increased FDG uptake with maximum standardised uptake values (SUV) of 8.4 (Figure 4a), suggesting a primary cardiac malignancy and faint FDG uptake was seen in D8, D9 and D10 vertebral bodies (Figure 4b, arrowhead) and pulmonary nodules (Figure 4b, arrow) suggesting metastasis.

Background

Primary cardiac angiosarcoma is the most frequent primary malignant tumour of the heart, belonging to a rare group of soft tissue malignancies with the most terrible prognosis. These tumours tend to arise from vascular or lymphatic endothelium with a predilection for the head and neck regions [5].

Approximately 80%–90% of cardiovascular angiosarcomas occur in the right atrium near the atrioventricular sulcus [1]. Although it is less common in deep soft tissues, these are particularly likely to metastasise to the lung. Other frequent sites for metastatic spread include the bone, liver, and lymph nodes [2].

Clinical Perspective

The clinical presentation of these patients often depends on the area of infiltration into the myocardium. At times, it can be missed altogether, only being diagnosed at autopsy. Therefore, early diagnosis is a crucial step leading toward its timely intervention.

Imaging Perspective

Metastatic angiosarcoma shows a wide variety of radiographic manifestations. The most common CT finding in lung metastasis is multiple solid nodular lesions [5], which are often haemorrhagic in nature. Few of the nodules can show punctate calcifications, a radiological expression of dystrophic calcifications due to haemorrhagic necrosis [3]. The other distinctive appearances include multiple thin-walled cysts [5]. A few of the cysts also show air-fluid levels, with solid material, a “halo sign” indicating recent haemorrhage [4], and some cysts show penetrating blood vessels. The haemorrhagic change is considered to be a characteristic finding in metastatic angiosarcoma, which may be due to the fragility of the neovascular tissue, predisposing the vessels to form thrombosis and rupture.

Due to the non-specificity of clinical features and biological behaviour, the final diagnosis must be confirmed by histopathological and immunohistochemical analysis. In our case, the patient underwent a biopsy from one of the pulmonary nodules. The histopathological examination showed the presence of spindle cells with immunohistochemistry staining, CD31, and CD34 positivity, confirming the endothelial origin of the tumour.

Outcome

The current treatment plan includes a multidisciplinary approach combining surgical resection, radiotherapy, and chemotherapy. Recently, there have been reports demonstrating better results on using proton beam therapy combined with chemotherapy for cardiac angiosarcoma [7].

In the present case, the patient was treated with Paclitaxel. After 9 weeks of chemotherapy, follow-up imaging with FDG PET-CT showed regression in the size of the primary lesion (Figure 5b, arrowhead), the pulmonary metastatic nodules, and sclerotic bone metastasis remained status quo.

Take Home Message / Teaching Points

Evaluation and diagnosis of primary cardiac angiosarcoma can be complex due to the rarity of its occurrences, non-specific symptoms, and frequently found pulmonary metastasis at the time of diagnosis. Confusion exists when the concepts overlap concerning excavating, cavitary, and cystic pulmonary metastatic tumours. The cysts are often thin-walled, bulla-like with or without accompanying any nodular lesions in cystic pulmonary metastasis. Whereas, cysts with penetrating blood vessels or bronchi are often the distinctive characteristics of metastatic pulmonary angiosarcoma [5].

Written informed patient consent for publication has been obtained.