Cutaneous angiosarcoma is a rare but well-recognized complication after radiation therapy. Atypical post-radiation vascular lesions (AVLs) with a benign course have been described recently, but few cases with limited follow-up have been studied so far. A total of 42 cases diagnosed as either radiation-associated cutaneous vascular lesions or angiosarcoma were retrieved from departmental and consultation files from 1995 to 2003. Hematoxylin and eosin-stained sections and clinical as well as follow-up data were evaluated. All patients were female with a median age of 59 years (range, 36-90 years). Presentation ranged from small erythematous/violaceous papules or nodules to large plaques with discoloration located on the chest wall (35), abdomen (2), shoulder, groin, flank, axilla, and lower leg (1 each). Reasons for radiation included breast carcinoma (35 cases) and a variety of other lesions (mainly malignant disease). Size range was 0.1 to 20 cm. Angiosarcomas presented as larger lesions (median, 7.5 cm) compared with AVLs (median, 0.5 cm). The time interval from radiation was significantly shorter for the development of AVL (median, 3.5 years) compared with cutaneous angiosarcoma (median, 6 years). Histologic evaluation revealed 26 lesions meeting criteria for angiosarcoma, ranging from morphologically low-grade to high-grade; 16 cases were classified as AVLs. These were fairly well-circumscribed lesions confined within superficial to mid dermis and composed of complex anastomosing and focally dilated vascular spaces. Some showed prominent hyperchromatic endothelial cells, while others were characterized by areas with a dissecting growth pattern within dermal collagen. Endothelial multilayering was absent. Clinical follow-up, available for 36 patients (range, 2-84 months; median, 17 months), revealed 4 patients who died of disease, 4 patients had systemic metastasis, and 12 patients with local recurrence. All patients with systemic relapse had an initial diagnosis of angiosarcoma. One patient with an AVL had a recurrence at the same site, 3 patients developed additional new lesions, and 1 patient developed multiple small papules on the chest wall, which progressed from an AVL to angiosarcoma. This study outlines the morphologic spectrum of radiation-associated cutaneous AVLs. No adverse outcome has been observed so far in this more benign subset of cases, but longer-term follow-up is necessary.