Endovascular papillary angioendothelioma (Dabska tumor) of bone.

Endovascular papillary angioendothelioma, also known as Dabska tumor, is a rare vascular neoplasm that usually involves the skin or subcutaneous tissue of children. There have been no reported cases of this lesion occurring in bone. We report a Dabska tumor in the distal femur of a 45-year-old woman who, clinically and radiologically, was felt to have an osteoid osteoma. Histologic study of the lesion showed a hemangioma with budding fronds of endothelial cells, a feature characteristic of the Dabska tumor. We feel that the lesion arose in a pre-existing hemangioma, a hypothesis suggested in a few other case reports. Endovascular papillary angioendothelioma is a low-grade malignant neoplasm, although only one patient has died due to this lesion. Our patient is asymptomatic without evidence of recurrence 1 year post curettage.