<unk>  is a hematological disorder in which the bone marrow is replaced with collagenous connective tissue and progressive fibrosis, replacing the bone marrow with a scar tissue and hence disrupting the normal production of blood cells which leads to pancytopenia. It is also classified as a myeloproliferative disorder. The term<unk>  alone usually refers to primary<unk>  (PMF), also known as chronic idiopathic<unk>  (CIMF); the terms idiopathic and primary mean that the disease is of unknown or spontaneous origin. This is in contrast with<unk>  that develops secondary to polycythemia vera, essential thrombocythemia, leukemia, or lymphoma (secondary<unk> .<unk>  is a form of myeloid metaplasia, which refers to a change in cell type in the blood-forming tissue of the bone marrow, and often the two terms are used synonymously. Genes involved in the pathogenesis of<unk>  include JAK2, CALR, and MPL.<unk>  must be differentiated from other diseases that cause diffuse bone sclerosis, such as sickle cell disease, hyperthyroidism, sclerosing bone dysplasia, osteoblastic metastases, and Paget's disease.Myelofibrosis must be differentiated from other diseases that cause splenomegaly, such as anemia, CML, polycythemia rubra vera, cirrhosis, infections, neoplastic, and lipid storage disorders. The prevalence of<unk>  is approximately 1 per 100,000 individuals worldwide.<unk>  is a disease that tends to affect the middle-aged and elderly population. The mean age at diagnosis is 60 years. Males are more commonly affected with<unk>  than females. The male to female ratio is approximately 1.5 to 1.<unk>  usually affects individuals of the Ashkenazi Jews race. African American, Latin American, and Asian individuals are less likely to develop<unk> . Common risk factors in the development of<unk>  may be age, other myeloproliferative disorders, radiation, or industrial chemical exposure.<unk>  has a very indolent course. If left untreated,<unk>  may progress to develop acute myelogenous leukemia, thrombohemorrhagic events, and progressive marrow failure. Common complications of<unk>  include infections, bleeding, hepatic failure, heart failure, and gout. Prognosis is generally poor and the median survival for<unk>  is 3.5 years to 5.5 years, but patients younger than 55 years have a median survival of 11 years. According to the World Health Organization (WHO) diagnostic criteria for primary<unk> , polycythemia vera, and essential thrombocythemia, the diagnosis of primary<unk>  is made when all three of the following major diagnostic criteria and at least two minor criteria are met. Symptoms of<unk>  include left upper quadrant abdominal pain, bruising, easy bleeding, pale skin, and frequent infections. Common physical examination findings of<unk>  include pallor, petechiae, lymphadenopathy, hepatomegaly, and splenomegaly. Laboratory findings consistent with the diagnosis of<unk>  include decreased red blood cells, normochromic normocytic anemia, tear-drop shaped RBCs, thrombocytopenia, and raised levels of lactate dehydrogenase. X-ray may be helpful in the diagnosis of<unk> . Findings on x-ray suggestive of<unk>  include osteosclerosis at different sites of the body, which tends to be diffuse and devoid of architectural distortion. CT scan and MRI may be helpful in the diagnosis of<unk> . Findings on CT scan suggestive of<unk>  include diffuse bone sclerosis. Findings on MRI suggestive of<unk>  include diffuse decrease bone marrow signal intensity. Bone marrow biopsy is the imaging modality of choice for<unk> . A bone marrow biopsy will reveal collagen fibrosis that has replaced the bone marrow. Other diagnostic studies for<unk>  include JAK2 mutation analysis testing and bone scan. Red blood cell transfusion, danazol therapy, or thalidomide are recommended for patients who develop anemia. Ruxolitinib, an inhibitor of JAK1 and JAK2, can reduce the splenomegaly and the debilitating symptoms of weight loss, fatigue, and night sweats for patients with JAK2-positive or JAK2-negative primary<unk> , post–essential thrombocythemia<unk> , or post–polycythemia vera<unk> . Hydroxyurea, chemotherapy, radiotherapy, or splenectomy are recommended for patients who develop splenomegaly. Surgery is not the first-line treatment option for patients with<unk> . Splenectomy is usually reserved for patients with massive splenomegaly unresponsive to conservative treatment. The only known cure is allogeneic stem cell transplantation, but this approach involves significant risks.Future and investigational therapies involve immunomodulatory drugs, histone deacetylase inhibitors, newer generation drugs of already existing medications and drugs targeting pathways other than the JAK/STAT. The goal is to limit the need for allogeneic stem cell transplantation.
Myelofibrosis
Myelodysplastic syndrome
Myeloid leukemia
Chronic myelogenous leukemia
Acute myeloid leukemia
Aplastic anemia
Polycythemia vera
Macroglobulinemia