A total of 4 patients with DFSP were referred from the dermatologic surgery unit at Columbia University Medical Center to receive neoadjuvant imatinib therapy before MMS. The Table compares the tumor characteristics, treatment regimens, and percentage of tumor reduction in the 4 patients who were treated with imatinib before surgery. The lesions, which were located on the scalp, abdomen, thigh, and ankle, ranged from 2.0 to 8.6 cm in the X dimension and from 2.7 to 14.0 cm in the Y dimension. Of the 4 imatinib-treated patients, 2 had recurrent lesions and 2 had locally advanced primary DFSP. The median duration of treatment with imatinib was 3 months. The drug was administered at a dosage of 800 mg/d in 2 patients and at lower dosages in 2 patients. One patient requested a dose of 400 mg once a day because she was hesitant to take a new medication. Given the other patient's history of multiple comorbidities, which included hypertension, diabetes, and obesity, the medical oncologist adjusted the initial dose to 600 mg/d to monitor for adverse events, with the goal of gradually increasing to the target dose if tolerated. All 4 patients tolerated their starting doses and showed a clinical response. As a result, no further dosage changes were made during the remainder of the treatment periods. Three patients were treated for 3 to 3½ months and experienced initial adverse effects consisting of fatigue, nausea, headache, dizziness, and diarrhea, which resolved within several weeks. The remaining patient was treated for 7 months and complained of dry skin and flank pain during the treatment. Despite these adverse effects, all patients tolerated the drug without requiring dose reduction or discontinuation. All 4 patients responded to imatinib therapy with a reduction in tumor size and thickness, achieving a reduction in preoperative tumor size, measured in the X and Y dimensions, between 18.9% and 61.6%, with an average size reduction of 36.9%. On pretreatment histopathologic examination, all lesions exhibited spindle-shaped cells in a typical storiform pattern. After treatment with imatinib, the histopathologic area showing decreased cellularity approached 100%. Also, there was production of hyalinized material throughout the tumors (Figure 1 and Figure 2).