Analysis Of Clinical Characteristics Of Extramedullary Blast Crisis In Chronic Myelogenous Leukemia

Objective: To summarize the clinical characteristics,laboratory examinations,treatment strategies and prognosis of 15 patients with extramedullary blast crisis of chronic myelogenous leukemia(CML)in our hospital.Methods: Retrospective analysis was performed on 15 patients with extramedullary blast crisis of CML diagnosed in our hospital from January 2006 to January 2021.The clinical data of these 15 patients,including clinical characteristics,laboratory examinations,immunological examinations,cytogenetics and molecular biology examinations,pathological biopsy,fluorescence in situ hybridization(FISH)analysis and treatment prognosis were analyzed,and review related literature.Results: Among the 15 patients with extramedullary blast crisis of CML,9 male patients and 6 female patients,with a median age of 47 years(19-72 years).Hematographic abnormalities were observed in these 15 cases and serum lactate dehydrogenase level was elevated in 11 cases.9 cases were newly diagnosed extramedullary blast crisis of CML,and 6cases progressed from chronic phase to extramedullary blast crisis.Blast cells retain myeloid features in 10 patients,blast lineages are lymphoid in 4 patients and 1 patient was undifferentiated phenotype.There were 2 cases of mutations in the kinase region of ABL.The clinical manifestations are mostly fatigue,fever,and enlarged superficial lymph nodes.A few patients have chest tightness,low back pain,weight loss,etc.as the main manifestations.TKI was the main treatment,11 patients were treated with TKI monotherapy or combined with chemotherapy,transplantation and other treatments,2 patients were treated with hydroxyurea,1 patient received surgery to remove extramedullary lesions,and 1 patient was treated with surgery and chemotherapy.All patients were followed up to January 1,2021.There were 3patients survived and 12 patients died,with a median survival of 17 months(0-89 months).Conclusions: Extramedullary blast crisis of CML are infrequent presence in clinical practice,extremely rarely the cases of newly diagnosed CML with extramedullary blast crisis.Extramedullary blast crisis can occur at any stage of CML.Some non-superficial extramedullary lesions are relatively insipid and easily to be ignored in clinical practice.Diagnosis depends on the results of pathological biopsy of extramedullary lesions combined with FISH and other examination results.In the era when FISH technology was not widely used,it was often difficult to differentiate from CML with lymphoma.There are no standard treatment strategies for extramedullary blast crisis of CML until now.And prognosis of these patients were poor,therefore,early diagnosis and early treatment are the key factors affecting the prognosis.