We have studied eight cases of an acquired lymphatic endothelial lesion for which we propose the name "benign lymphangioendothelioma." The lesions developed as solitary, slowly extending, erythematous macules and plaques, usually occurring on the extremities or the shoulders in adolescents or adults. The characteristic histopathologic feature is permeation of the dermal collagen by flattened, endothelium-lined channels and spaces. Hemorrhage, iron deposition, and inflammation were not part of the lesion. Ulex europaeus agglutinin I labeled the lesional endothelial cells consistently, but factor VIII-related antigen labeling was negative. This histologic pattern and the special studies suggested a lymphatic lesion. Surgical excision, performed in six patients, was not followed by recurrence.