Primary angiosarcoma of the breast is a rare and often misdiagnosed disease. The most common clinical presentation is a painless mass in the affected breast, but the often varied presentation and the high incidence of histologic misdiagnosis make early detection rare. The tumor size and the histologic type correlate with the prognosis. The treatment for angiosarcoma of the breast is early and complete surgical excision of the mass with adequate margins. Axillary dissection is not indicated because the predilection for nodal metastasis is rare. The definitive role of adjuvant therapy remains undetermined. Chemotherapy and radiotherapy may play an important role in survival; however, the data are inconclusive. A high index of suspicion for angiosarcoma is a crucial tool in its proper diagnosis and treatment. It should always be noted that a vascular lesion that is associated with any breast mass is an angiosarcoma until proven otherwise.