The aim of this study was to analyze the breast MRI characteristics of radiation-associated breast angiosarcomas (RAS).

In this institutional review board (IRB)-approved retrospective study, fifty-six (57) women were diagnosed with pathology confirmed RAS during the study period (January 1999 - May 2013). Seventeen women underwent pre-treatment breast MRI (prior to surgical resection or chemotherapy), of which 16 studies were available for review. Imaging features of these tumors were evaluated by two radiologists and correlated with clinical management and outcomes.

Median age of patients at original breast cancer diagnosis was 69.3 years (range 42-84 years), with average time from initial radiation therapy to diagnosis of RAS of 7.3 years (range 5.1 – 9.5 years). Nine women had mammogram (9/16, 56%) and five had breast ultrasound (US) (5/16, 31%) prior to MRI, which demonstrated expected, non-suspicious findings of skin thickening in over half the cases. Four patients had distinct intraparenchymal masses on US, mammogram, and MRI. MRI findings included diffuse T2 high signal skin thickening (16/16, 100%). Nearly half (7/16, 44%) of patients had T2 low signal intensity lesions; all lesions rapidly enhanced on post-contrast T1 weighted imaging. All women underwent surgical resection, with 8/16 (50%) receiving neoadjuvant chemotherapy. Four women died during the study period.

Clinical, mammographic and sonographic findings of RAS are non-specific and may be occult on conventional breast imaging; MRI findings of RAS include rapidly enhancing dermal and intraparenchymal lesions, some of which are low signal on T2 weighted imaging.