Atypical postradiation vascular proliferation (APRVP), also known as atypical vascular lesion (AVL), is a benign and rare complication of radiation therapy. APRVP occurs mostly in females, as it most commonly develops in radiation fields for breast cancer. It has also been reported after radiation for other malignancies.

APRVP may present at any time after radiation therapy. The median time to onset was 6 years postradiation in one large retrospective review. Clinically, APRVP is heterogenous. Most reported cases present as a single reddish, violaceous, skin-colored or brownish papule that develops in a prior radiation field; however, more than one may also be seen, and the primary lesion may be a macule, patch, or plaque. Telangiectasia and sclerosis may be further clinical features. APRVPs are generally asymptomatic, but pain and pruritus have been reported in a small percentage of patients.

There is debate in the literature regarding whether APRVP is a precursor to radiation-associated cutaneous angiosarcoma or not. Concurrently obtained biopsies in some cases have shown that both conditions may be present simultaneously. The development of angiosarcoma has been documented in very few cases, with the time to diagnosis after APRVP diagnosis varying from 54 to 235 days.