Myelofibrosis

Myelofibrosis is a chronic hematologic disorder characterized by replacement of bone marrow with fibrous tissue, extramedullary hematopoiesis, and variable cytopenias, producing systemic symptoms and splenomegaly. The condition is associated with clonal hematopoietic stem cell aberrations discovered in studies by groups at institutions such as National Institutes of Health, Mayo Clinic, and Dana-Farber Cancer Institute. Historically, descriptions of marrow fibrosis appear in literature contemporary with work at Johns Hopkins Hospital and case series reported through centers including Fred Hutchinson Cancer Center and Memorial Sloan Kettering Cancer Center.

Signs and symptoms

Patients typically present with progressive fatigue, weight loss, night sweats and fever that often prompt referral to centers like Cleveland Clinic or Mount Sinai Hospital for hematology consultation. Massive splenomegaly causing early satiety or left upper quadrant pain frequently leads to imaging at facilities such as Mayo Clinic or Massachusetts General Hospital and may produce portal hypertension evaluated by teams at University of California, San Francisco and Stanford University Medical Center. Anemia-related pallor, bleeding diathesis and recurrent infections often result in visits to emergency departments at institutions such as Royal Marsden Hospital and Karolinska University Hospital, while constitutional symptoms prompt oncologic assessment at centers like MD Anderson Cancer Center and H. Lee Moffitt Cancer Center & Research Institute. Skeletal pain and osteosclerosis may be mistaken for metastatic disease referred to multidisciplinary boards at Memorial Sloan Kettering Cancer Center, Royal Free Hospital, and Guy's and St Thomas' NHS Foundation Trust.

Causes and pathophysiology

Clonal mutations in hematopoietic stem cells—including activating variants in genes first characterized by research groups at University of Helsinki and Brigham and Women's Hospital—drive disease biology, with recurrent lesions in genes such as JAK2, CALR and MPL identified by laboratories associated with Wellcome Trust Sanger Institute and Broad Institute. Dysregulated signaling through pathways studied in molecular oncology programs at Cold Spring Harbor Laboratory and Max Planck Institute leads to fibroblast activation, cytokine release involving interleukins and transforming growth factor β, and marrow stromal remodeling documented in collaborations including European Molecular Biology Laboratory and Institut Pasteur. Secondary forms arising after polycythemia vera or essential thrombocythemia are described in longitudinal cohorts maintained at European Society for Medical Oncology centers and registries managed by International Working Group on Myeloproliferative Neoplasms Research and Treatment. Environmental or iatrogenic contributors have been considered in historical studies from Centers for Disease Control and Prevention and occupational investigations at National Institute for Occupational Safety and Health.

Diagnosis

Diagnosis integrates peripheral blood smear reviewed by hematopathology services at institutions such as Royal College of Pathologists and bone marrow biopsy interpreted in reference laboratories at Johns Hopkins Hospital and Mayo Clinic. Molecular testing for JAK2 V617F, CALR exon 9, and MPL W515 mutations is performed in accreditation laboratories affiliated with College of American Pathologists and research centers like University of Cambridge and University of Oxford. Imaging to assess splenomegaly and extramedullary hematopoiesis is commonly obtained at radiology departments in Massachusetts General Hospital and Karolinska University Hospital, while cytogenetic studies are provided by cytogenetics units at Memorial Sloan Kettering Cancer Center and Fred Hutchinson Cancer Research Center. Diagnostic criteria are codified by consensus groups including World Health Organization panels and validated in trials by cooperative groups such as European LeukemiaNet and the National Comprehensive Cancer Network.

Treatment and management

Management strategies range from observation to targeted therapy and transplantation, with therapeutic algorithms developed by panels at National Comprehensive Cancer Network, European Society for Medical Oncology and academic centers including MD Anderson Cancer Center and Mayo Clinic. JAK inhibitors such as ruxolitinib—developed in collaboration with pharmaceutical research teams at Novartis and evaluated in trials sponsored by organizations like Food and Drug Administration and European Medicines Agency—alleviate splenomegaly and symptoms. Allogeneic hematopoietic stem cell transplantation remains the only curative option and is performed at transplant centers such as Fred Hutchinson Cancer Research Center, University of Minnesota Medical Center and City of Hope National Medical Center, guided by donor registries like Be The Match and transplant networks coordinated by European Society for Blood and Marrow Transplantation. Supportive care including transfusions, erythropoiesis-stimulating agents and iron chelation is provided following guidelines from groups such as American Society of Hematology and British Society for Haematology, while clinical trials at institutions like Dana-Farber Cancer Institute and Stanford University Medical Center investigate novel agents including telomerase inhibitors and epigenetic therapies developed in partnerships with companies such as Gilead Sciences and Bristol Myers Squibb.

Prognosis and complications

Prognosis varies widely and is stratified using scoring systems validated by investigators at Mayo Clinic, Princess Margaret Cancer Centre, and University of Florence; these tools incorporate age, blood counts and karyotype findings reported by cytogenetic units at Memorial Sloan Kettering Cancer Center and Fred Hutchinson Cancer Center. Complications include progressive marrow failure necessitating transfusion support managed at centers like Royal Infirmary of Edinburgh and thrombosis or hemorrhage treated in collaboration with vascular services at Guy's and St Thomas' NHS Foundation Trust and Mount Sinai Hospital. Transformation to acute myeloid leukemia is a recognized endpoint monitored in longitudinal cohorts maintained by European LeukemiaNet and the International Working Group on Myeloproliferative Neoplasms Research and Treatment, and comorbidity management often involves multidisciplinary teams at institutions such as Cleveland Clinic and Johns Hopkins Hospital.

Category:Myeloproliferative neoplasms