Atypical vascular lesions extending outside the radiation field: a diagnostic challenge.

Atypical vascular lesion (AVL) is an uncommon, benign vascular proliferation seen in previously irradiated skin, most commonly after radiotherapy for breast cancer. Atypical vascular lesion and angiosarcoma may share overlapping clinical and histopathologic features. We report the first case of AVL occurring outside the field of radiation. This patient's clinical course and histopathology was overall consistent with AVL, including two biopsies with focal MYC positivity. However, due to variations in the interpretation of her histopathology, the management plans devised by two centers involved in her care were widely discordant and she was treated with chemotherapy and extensive surgery for angiosarcoma. Great care must be taken to distinguish between these entities, as treatment for angiosarcoma may be associated with significant morbidity.