Sweet's syndrome may occur in three settings in patients with hematologic disorders, such as leukemia: (1) a paraneoplastic syndrome heralding either the initial discovery of an unsuspected malignancy or the recurrence of a previously treated cancer; (2) a drug-induced dermatosis subsequent to the patient being treated with either all-trans retinoic acid, bortezomib, granulocyte-colony stimulating factor, or imatinib mesylate; or (3) a dermatosis in which the skin lesions concurrently demonstrate leukemia cutis [1]. This evidence concerns the gene CSF3 and hematologic disorder.