Malignant endovascular papillary angioendothelioma. Cutaneous borderline tumor.

Malignant endovascular papillary angioendothelioma, a rare but distinctive vascular tumor of childhood, was first described in 1969. It was termed malignant because of its mitotic activity, areas of necrosis, and demonstrated ability to metastasize to regional lymph nodes. Despite these features it had a uniformly good prognosis. We report an example of this lesion in a 6-year-old boy that does not show malignant histologic features. Based on its good long-term prognosis and variable histologic features, this lesion is better classified as a borderline vascular tumor.