Clinical and histopathologic observations of the action of imiquimod in an epithelioid hemangioendothelioma and Paget's mammary disease

An epithelioid hemangioendothelioma and Paget's disease of the breast were treated with topical imiquimod 5% cream with very impressive results. In both of the tumors complete disappearance of the lesions occurred. In this article, in addition to describing the treatment approach, the findings in biopsy specimens of the epithelioid hemangioendothelioma and the Paget's disease before, during, and after therapy will be described. The histologic findings show ample evidence that there is both a lymphocytic T helper 1-like and T helper 2-like response from imiquimod. Direct evidence of lymphocytotoxicity was found. Furthermore, mast cells appear to be involved in the development of regression in the vascular tumor. Although the study is very limited and reports only two cases, the results are striking. We considered it important to describe these findings because of their possible use in developing strategies for the application of imiquimod in the treatment of other tumors in human beings.