Directory
Heterogeneous marrow signal is an abnormal MRI finding characterized by areas of varying brightness within the bone marrow. It can indicate various underlying conditions. Leukemia, an uncontrolled proliferation of abnormal white blood cells, can result in heterogeneous marrow signal due to abnormal cell infiltration. Osteomyelitis, a bone infection, can also cause heterogeneous marrow signal as…
Red marrow reconversion, which refers to the transformation of yellow marrow (fatty tissue) back into active red marrow (blood cell production site), is not necessarily indicative of cancer. It can occur as a response to increased demand for blood cells due to conditions such as anemia, infection, or certain medications. However, in some cases, red…
Bone marrow is a soft tissue found in the cavities of bones. It produces blood cells, including red blood cells, white blood cells, and platelets. Histologically, bone marrow consists of reticular connective tissue with numerous blood vessels and sinusoids. Two main types of bone marrow are recognized: red bone marrow, which is highly vascularized and…
Hyperplastic red marrow, a hallmark of myeloproliferative neoplasms, is characterized by an increase in cellularity of the bone marrow with predominantly erythroid precursors. This results in increased production of red blood cells, leading to elevated hematocrit and hemoglobin levels. It can also cause enlargement of the spleen (splenomegaly) and liver (hepatomegaly), as well as constitutional…
Bone marrow hyperplasia, characterized by excessive bone marrow activity, often signifies underlying entities with high closeness ratings, indicating a strong association. These entities include myeloid neoplasms and conditions associated with increased hematopoietic stem cell activity. Pathologically, it involves dysregulated cell cycle progression, prolonged hematopoietic cell survival, and altered cell signaling pathways. Clinically, it manifests as…
Hypocellularity of bone marrow, a condition characterized by a decrease in cellularity, occurs when the bone marrow fails to produce an adequate number of blood cells. This can lead to cytopenias, resulting in anemia, neutropenia, and thrombocytopenia. Hypocellularity can be caused by myelofibrosis, leukemia, lymphoma, and myelodysplastic syndromes. Diagnostic tests include bone marrow biopsy, blood…
Bone marrow cellularity refers to the composition and activity of cells within the bone marrow microenvironment, including hematopoietic stem cells, progenitor cells, erythroid and myeloid cells, lymphoid cells, megakaryocytes, and stromal cells. It is essential for maintaining blood formation and immune function. Alterations in cellularity, such as decreased cell counts or abnormal cell types, can…
Hyperplasia in bone marrow refers to an abnormal increase in the number of cells within the bone marrow, typically due to an underlying stimulus or disease process. It can manifest as reactive hyperplasia, where normal cells proliferate in response to a trigger, or as a feature of myeloproliferative neoplasms, primary bone marrow malignancies such as…
Bone marrow, the blood factory, produces blood cells via hematopoiesis, where stem cells differentiate into various blood types. Hematopoiesis involves the production of platelets, clotting cells; red blood cells, oxygen carriers; and white blood cells, immune defenders. Bone marrow aspiration extracts samples for analysis, while a biopsy offers a more in-depth examination. Bone marrow transplants,…
Hemosiderin-laden macrophages are characterized by the presence of iron-containing hemosiderin within their cytoplasm. This occurs in conditions of iron overload, where excess iron accumulates in macrophages, primarily in the liver. Hemosiderosis, a condition caused by iron deposition in tissues, contributes to the formation of hemosiderin-laden macrophages. These macrophages play a crucial role in iron storage,…
Peroxisome macrophage inflammation arises when peroxisomes, intracellular organelles involved in lipid metabolism, release their contents, leading to inflammation. Macrophages, immune cells that engulf foreign substances, recognize the released peroxisome contents as danger signals, triggering an inflammatory response characterized by the release of cytokines, chemokines, and proteases. This inflammation aims to clear the debris and promote…
Macrophages are immune cells that play a crucial role in phagocytosis, the engulfment of dead or foreign particles. They release perforin and granzyme, which are proteins that induce apoptosis, or programmed cell death, in target cells. Perforin creates pores in the cell membrane, allowing granzyme to enter and activate caspases, enzymes that execute the apoptotic…
