Atypical vascular lesions (AVLs) are vascular proliferations that develop after surgery and radiation for breast carcinoma and may represent precursors to angiosarcoma. AVLs are not well-known entities and currently lack official prognostic factors and guidelines for surgical treatment. We report the case of a patient who developed an AVL, vascular type, 4 years after lumpectomy and radiation therapy for ductal carcinoma in situ of the breast. The patient underwent wide local excision with 1-cm margins with subsequent pathologic examination confirming complete excision of the residual atypical vascular proliferation. This case highlights the importance of close cutaneous surveillance in patients with a history of surgery and radiation for breast carcinoma, and a low threshold for biopsy. More studies are needed to further delineate the risk of AVLs progressing to angiosarcoma and to identify histologic features or immunophenotypic markers, which may be predictive of this risk. Furthermore, formal treatment recommendations for these enigmatic entities would be helpful.