- Myelophthisic Anemia is a generic term referring to anemia caused by physical infiltration of the bone marrow by an exogenous, space-occupying lesion. Infiltrating lesions can disturb hematopoiesis either by physically replacing native marrow, disturbing its architecture, or yielding reactive fibrosis. Whatever the case, the marrow's ability to produce blood cells is reduced, typically yielding pancytopenia that includes some combination of normocytic anemia, thrombocytopenia, and neutropenia.
- The nature of the infiltrating lesions are often metastatic malignancies or infectious granulomatous processes. Classic malignant culprits include metastatic breast carcinoma, bronchogenic carcinoma, and prostate adenocarcinoma. Infectious granulomatous diseases include Mycobacterium tuberculosis and a variety of fungal causes in immunocompromised patients.
- As a point of interest, marrow replacement is accompanied by egress of blood cell progenitors, such as erythroblasts and myeloblasts, into the peripheral blood which can be seen on peripheral blood smear.