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MD, have indicated no significant interest with commercial supporters.I n the presurgical treatment of locally advanced and metastatic dermatofibrosarcoma protuberans (DFSP), imatinib mesylate (Gleevec or STI-571, Novartis, Basel, Switzerland) has been used with some success in six case reports and a clinical trial. 1-6 This is our case report of a patient with DFSP who after two previous resections with subsequent recurrence was presurgically treated with imatinib mesylate, underwent a third resection, and is now tumor-free for 16 months. The standard of care for DFSP has been wide local resection; however, the rate of recurrence is as high as 60%. 7-9 Fibrosarcomatous histopathology in the tumor is commonly associated with recurrence and increased risk of metastasis, most commonly to the lungs. 10,11 A defining characteristic of DFSP is the aberrant constitutional overexpression of platelet-derived growth factor b (PDGFB), which serves to activate plateletderived growth factor receptor b (PDGFRB) and its tyrosine kinases through an autocrine mechanism that results in cell growth and proliferation. This overexpression of PDGFB is the result of a fusion gene consisting of collagen type I-a1 gene and PDGFB-chain gene from the rearrangement of chromosomes 17 and 22, leading to a supranumery ring [r(17;22)] or reciprocal translocation [t(17;22)]. 12,13 Imatinib mesylate is FDA-approved for the treatment of chronic myelogenous leukemia and has also been used successfully against gastrointestinal stromal tumors. Like DFSP, both have constitutional overstimulation of tyrosine kinase receptors, bcr-abl and c-kit, respectively. It works as a protein tyrosine kinase inhibitor and thus disrupts this autocrine stimulation (Figure 1). 14-16 With this knowledge, the use of imatinib mesylate in the treatment of DFSP has also been investigated, and there are now six case reports and a clinical trial concerning its use as the sole treatment in metastatic, inoperable DFSP or presurgically in locally advanced DFSP. These publications demonstrate that patients with DFSP known to have the t(17;22) or r(17;22) rearrangement with subsequent PDGFB overexpression obtain partial or complete response using imatinib mesylate, as shown clinically, as well as by radiologic and histologic evidence. Many of the patients had a Figure 1. Diagram demonstrating imatinib mesylate (Gleevec) mechanism of action as a protein tyrosine kinase inhibitor. (