With improved outcomes associated with radiotherapy (RT), post-irradiation tumors are increasingly seen in long-term cancer survivors. We report a case of a young woman who presented with a three-year history of a vascular lesion on the temple, previously irradiated for a childhood brain tumor. The history of radiation, the clinical appearance, and the biopsy findings of an atypical vascular proliferation in the dermis, were worrisome for a malignant vascular neoplasm and prompted surgical excision. However, further tissue analysis of the excised specimen confirmed a benign atypical vascular lesion (AVL) overlying a banal pilar cyst. Distinguishing post-radiation benign from malignant vascular lesions can be difficult because they share overlapping clinical and histopathologic features. Thus, any vascular lesion that occurs in a previously irradiated field should be excised completely with tumor-free margins and examined histologically.