Lymphatic invasion in Spitz nevi.

Forty-nine Spitz nevi occurring in children were reviewed and sampled extensively in order to assess the incidence of vascular invasion. Evidence of vascular invasion was found in seven (14.3%) cases. The endothelium of such vessels was negative on immunoperoxidase staining for Factor VIII-related antigen suggesting the nevus cells to be in lymphatic channels and not blood vessels. No unusual histological or clinical features characterized the group. All patients are alive and well some years after local excision therapy. It is concluded that lymphatic invasion by nevus cells in Spitz nevi is not uncommon and its presence should not tempt the pathologist into a diagnosis of melanoma.