Intravascular endothelial proliferations in children.

Six children who had benign cutaneous vascular lesions characterized by papillary or solid proliferation of the endothelial cells were seen in a 16-year period. In five of them, the lesions had the histologic features of the entity originally described by Masson and recently reported by Clearkin and Enzinger as intravascular papillary endothelial hyperplasia. In one of the five, the lesion appeared in the pure form within large vascular spaces, whereas in the remaining four it appeared as a very limited focal change in a hematoma. The authors agree with others that this lesion represents a peculiar variant of an organizing thrombus. The histologic features of the lesion in the sixth patient were compatible with the so-called "intravenous atypical vascular proliferation," another pseudomalignant vascular disorder recently described by Rosai and Akerman.