Primary angiosarcoma of the breast presenting with a benign vascular skin-like lesion and expanding hematoma: a case report of an extremely rare tumor.

Primary breast angiosarcoma is an extremely rare tumor type (0.05% of primary breast cancers) for which diagnosis can be difficult. They arise within the breast parenchyma and typically present as a breast mass. Here, we present the case of a 30-year-old female with spontaneous hypervascular skin on her right breast with progressive enlargement presenting as an expanding hematoma. A chest computed tomography revealed a hypervascular mass in the right breast abutting the pectoralis muscle and cystic changes within the mass. A core needle biopsy revealed an angiosarcoma. In this case study, we report a patient who, with no history of any known risk factors, presented with a benign vascular skin lesion as the first sign of angiosarcoma followed by an expanding hematoma, which is an extremely rare manifestation of the disease. Microscopic examination demonstrated a low-grade angiosarcoma on the skin, while a high-grade angiosarcoma was found in the breast parenchyma.