[A patient with acute Philadelphia-chromosome-positive mixed phenotype leukemia developing ecthyma gangrenosum while undergoing combined imatinib mesylate chemotherapy].

A 67-year-old woman with acute Philadelphia-chromosome-positive mixed phenotype leukemia developed bilateral periorbital ecthyma gangrenousum (EG) subsequent to periorbital edema while undergoing combined imatinib mesylate (imatinib) chemotherapy. Although initial periorbital edema was considered an imatinib side effect, the lesion deteriorated rapidly with high fever in the neutropenic phase, and the woman died of septic shock. Cultures from blood and exudative fluid grew Pseudomonas aeruginosa, after which EG was diagnosed. EG is a well-recognized emergent cutaneous infection most commonly associated with Pseudomonas aeruginosa bactremia. Because some patients present with EG a few days prior to developing life-threatening septicemia, it is important that EG be diagnosed correctly. Imatinib side effects such as edema are usually tolerable, and imatinib is widely used to treat Philadelphia-chromosome-positive leukemia, particularly in those with acute lymphoblastic leukemia, and neutropenic patients undergoing imatinib therapy are expected to increase in number. Delay in initiating appropriate therapy is correlated with poor outcome, so drug side effects and EG must be carefully differentiated when skin edema with surrounding erythema is noted in neutropenic patients undergoing imatinib therapy.