Anti-vimentin recognizes a 57-kDa intermediate filament initially isolated from mouse fibroblast culture. Anti-vimentin often serves as a useful control marker to ensure that the tissue has been properly preserved and processed.¹ Expression of vimentin, when used in conjunction with keratin, is helpful when distinguishing melanomas from undifferentiated carcinomas and large cell lymphomas. All melanomas and schwannomas react strongly with vimentin. It labels a variety of mesenchymal cells, including melanocytes, lymphocytes, endothelial cells, and fibroblasts. In the area of gynecologic tumors, uterine endometrioid adenocarcinomas display a highly characteristic immunophenotype, with coexpression of low molecular wt. cytokeratin and vimentin.^1-4