Primary
breast angiosarcoma is a very rare aggressive mesenchymal
tumor, which may represent only 0.04% of all
breast malignant tumors. We report a case of primary
angiosarcoma in the breast of a 22-year-old woman who presented with a mass in her right breast. Ultrasonography revealed a large heterogeneous lobulated mass lesion consistent with a
fibroadenoma or
phyllodes tumor. After a period of six months, she presented with nipple retraction, so a core needle biopsy was performed. Histopathology revealed a well differentiated
angiosarcoma (grade I/III), but in the
mastectomy specimen, numerous neoplastic multinucleated giant cells were evident, which resembled those found in other
sarcomas, such as
malignant fibrous histiocytoma or extra skeletal
osteogenic sarcoma, and this caused difficulty making the diagnosis. Using immunohistochemical (IHC) studies, neoplastic cells were positively stained for CD31, CD34, and
factor VIII-related
antigens, which confirmed that the
tumor was a high grade, poorly differentiated
angiosarcoma (grade III/III). In conclusion,
angiosarcomas may have different grade patterns in the same
tumor, and as a result it is necessary to examine the whole
tumor for definite grading. Imaging findings in
angiosarcomas are non-specific, therefore they may misdiagnosed, frequently by other benign lesions.