Retiform hemangioendothelioma

A 32-year-old white woman presented with a 2-year history of a gradually enlarging, asymptomatic, cutaneous and subcutaneous, 315-cm plaque with a nodular surface on the left upper thigh (Fig. 1). There were no other complaints or physical signs. The clinical differential diagnosis included: cutaneous lymphoma, metastatic adenocarcinoma, and dermatofibrosarcoma protuberans. A 6-mm punch biopsy was taken and showed numerous dilated vascular spaces in the upper dermis lined by monomorphic endothelial cells. Some of these vessels showed endovascular papillae with hyaline collagenous cores (Fig.2). In addition, there were solid nests of endothelial cells observed in the vicinity of the affected vessels. Lymphocytic infiltrate was conspicuous both within the endovascular papillae and the dermis. Most of the lymphocytes within the blood vessels occurred in close association with the endothelial cells. Staining with factor VIII related antigen was positive in the endothelial lining of the blood vessels, but not in the solid nests (Fig.3). At this stage, a diagnosis of Dabska's tumor was entertained; however, excision biopsy of the whole lesion showed the presence of very characteristic arborizing blood vessels (Fig.4), arranged in a retiform pattern, within the lower dermis. These blood vessels were lined by bland endothelial cells and contained, in some of them, endovascular papillary projections with collagenous cores. The papillary projections were lined by cuboidal endothelial cells occurring in close association with intravascular lymphocytes. The final diagnosis was retiform hemangioendothelioma. There was no recurrence or lymph node metastases during a follow-up period of 1.5 years.