Wilms Tumor 1 Expression in Vascular Neoplasms and Vascular Malformations

Background: Wilms tumor 1 (WT1) protein is expressed during angiogenesis and malignant transformation of endothelial cells and can be helpful to distinguish between proliferative and malformative vascular lesions. Methods: We evaluated retrospectively 117 vascular neoplasms and 50 vascular malformations. Vascular neoplasms included infantile hemangioma (n = 87), noninvoluting congenital hemangioma (n = 5), rapidly involuting congenital hemangioma (n = 3), tufted angioma (n = 8), pyogenic granuloma (n = 13), and spindle cell hemangioma (n = 1). Vascular malformations were lymphatic malformations (n = 28), venous malformations (n = 16), capillary malformation (n = 1), and stage II arteriovenous malformations (n = 5). Immunohistochemical stains for WT1 and GLUT1 were performed in all lesions. Results: All 117 vascular neoplasms showed positive expression of WT1, whereas all vascular malformations in our study were completely negative for WT1 except in arteriovenous malformations, where WT1 expression was positive. Conclusions: The comparison between vascular neoplasms and vascular malformations showed that GLUT1 expression is positive only in infantile hemangiomas, whereas WT1 positivity is found in all vascular neoplasms and in arteriovenous malformations. WT1 antibody is an ancillary test that can be helpful to differentiate vascular neoplasms from most vascular malformations.