RESUMO
Retiform hemangioendothelioma is a locally aggressive, rarely metastasizing, low-grade angiosarcoma characterized by intercommunicating vascular channels lined by hobnail or cuboidal endothelial cells, flanked by lymphocyte and hyaline sclerosis. Neoplastic endothelial cells usually express von Willebrand factor, CD31 and CD34, while the lymphocytic infiltrate shows a mixture of CD3+, T and CD20+ B cells. The authors describe a case of a 76-year-old female who presented with a soft, painless, ill-defined mass measuring 9 cm in her right gluteal region for the past 15 years, clinically suggestive of a lipoma. There was no regional lymphadenopathy. The mass was resected and sent for histopathological examination. The slow-growing lesion and the typical histomorphology led to the diagnosis of retiform hemangioendothelioma. The diagnosis was confirmed by immunohistochemistry using CD34 antibody, which strongly stained the endothelial cells. The patient was followed up for 6 months after the surgery and no recurrence was noted.