Imatinib-induced drug reaction with eosinophilia and systemic symptoms in solid tumors: a patient with dermatofibrosarcoma protuberans and successful desensitization management.

Drug reaction with eosinophilia and systemic symptoms (DRESS) is a severe, potentially life-threatening drug-induced hypersensitivity reaction, characterized by cutaneous eruptions, fever, diffuse lymphadenopathy, along with hypereosinophilia, and elevated liver function tests, which in severe cases may lead to fulminant hepatic failure and death. Although DRESS syndrome has been associated with over 50 different drugs including imatinib, it has never been reported in association with imatinib treatment in solid tumors. We recently treated a patient with metastatic dermatofibrosarcoma protuberans, a rare cutaneous mesenchymal tumor characterized by constitutive activation of the PDGFβ receptor and high sensitivity to imatinib therapy, who had a DRESS reaction to imatinib. Given an initial dramatic clinical and radiological response to treatment and lack of effective alternative targeted therapies, following imatinib discontinuation and resolution of DRESS, we cautiously reintroduced imatinib therapy using a desensitization protocol under the care of the allergy and immunologic clinic. Imatinib was carefully titrated from an initial dose of 50 mg to a target dose of 400 mg daily, while tapering down the prednisone dose. The patient was able to tolerate the treatment without recurrent episodes of DRESS or interruptions, and gained additional 6 months of clinical benefit from imatinib treatment. Although suspected causative drugs should not be reintroduced in DRESS whenever possible, in this case of metastatic disease and lack of effective alternative treatments, a carefully designed drug rechallenge helped minimize the risk of overt clinical reaction and resulted in an overall clinical benefit.