<unk>  can occur in the setting of chronic myeloproliferative disease (e.g. myelofibrosis), leukemia, lymphoma, and metastatic carcinoma or myeloma. It is common in people who have chronic idiopathic myelofibrosis. It has been linked to small-cell lung cancer, breast cancer or prostate cancer that metastasizes to the bone marrow. Currently, the most common cause is displacement of bone marrow by metastatic cancer (extramedullary hematopoiesis tends to be modest). Other causes include myeloproliferative disorders (especially late-stage or spent polycythemia vera), granulomatous diseases, and (lipid) storage diseases. Myelofibrosis can occur in all of these. Factors that may contribute to decreased RBC production include a decreased quantity of functioning hematopoietic tissue, disordered metabolism related to the underlying disorder, and, in some cases, erythrophagocytosis.
Myelophthisic anemia
Sideroblastic anemia
Myomatous erythrocytosis syndrome
Refractory anemia with ring sideroblasts
Refractory anemia with excess of blasts
Aplastic anemia
Hereditary elliptocytosis
Hemoglobinemia