Background: Angiosarcoma is rare, and information about its clinical features are limited. Therefore, a large scale study of angiosarcoma was performed in Japan.
Methods: Through a nationwide Japanese study, 99 cases of angiosarcoma were collected and their clinicopathologic findings were summarized relative to predisposing risk factors.
Results: The patient age at diagnosis was 3-92 years, (mean, 62 years), with a two to one male to female ratio. The head and face were the most common primary site (29 cases); other sites were liver (17); trunk (13): pleural cavity (6), chest wall (2), abdominal wall (2), buttock (2), inguinal region (1); heart (12); and extremities (7). The proven predisposing risk factors included chronic pyothorax for angiosarcoma in the pleural cavity (six), thorotrast in the liver (five), radiotherapy to the abdominal wall and buttock (four), and chronic limb edema of the forearm (one). Irrespective of primary sites, the majority of cases had metastases to lung in 72 cases, bone in 42, liver in 36, regional lymph nodes in 30, and adrenal gland in 24. The 2-year survival rate was 17%.
Conclusions: This study describes a different etiology in the development of angiosarcoma in patients from Japan compared with that of patients from Western countries, though the frequency of angiosarcoma among all soft-tissue sarcomas was similar in both areas. In Japan, chronic pyothorax, radiotherapy, and thorotrast proved to be distinctive causative factors of angiosarcoma.