A splenectomy was performed in a 37-year-old woman because of spontaneous rupture of the spleen. Primary angiosarcoma of the spleen was diagnosed postoperatively based on histology. Primary angiosarcoma of the spleen is a very rare neoplasm with disastrous prognosis. Immunohistochemical and ultrastructural examinations are necessary to verify the diagnosis because the histopathological picture of the tumor is variable. Due to the small number of reported cases, there are no guidelines for adjuvant or palliative therapy, and up to today all adjuvant means of radiotherapy and chemotherapy have not improved the prognosis of the patients.