Chronic neutrophilic leukemia (CNL) is a rare myeloproliferative neoplasm characterized by sustained neutrophilia and the absence of the Philadelphia chromosome or the BCR-ABL1 fusion gene. The present study reports the case of a 59-year-old Caucasian female that was referred to The Francisco Gentil Portuguese Institute of Oncology (Porto, Portugal) with constitutional symptoms (mainly asthenia), marked leukocytosis (51.33×109/l with 90% neutrophils), macrocytic anemia and splenomegaly. Bone marrow aspiration and biopsy revealed hypercellular marrow with clear predominance of segmented neutrophils. The karyotype was normal and the BCR-ABL1 fusion gene was not detected. After excluding a leukemoid reaction, a diagnosis of CNL was established. The clinical follow-up was complicated by hemorrhagic brain lesions and relapsing episodes of erythematous, well-demarcated and painful subcutaneous nodular lesions, consistent with Sweet's syndrome (SS). Multiple treatment strategies were administered, including use of hydroxyurea, imatinib and intensive chemotherapy. Nevertheless, progression was documented and the patient succumbed at 28 months post-diagnosis. The clinical course of CNL varies, and can be complicated by cerebral hemorrhage, blastic transformation or infection. Dermatological manifestations such as SS have seldom been reported in association. No evidence-based treatment currently exists and the majority of our knowledge is based on results from case reports and small series.
