myelophthisis

Myelophthisis is a form of bone marrow failure caused by replacement or destruction of normal hematopoietic tissue by an abnormal process within the marrow. The infiltrating tissue can be fibrous, tumorous, granulomatous, or otherwise displacing marrow elements, leading to ineffective hematopoiesis and varying degrees of cytopenias. A leukoerythroblastic blood picture, with teardrop red cells and circulating immature white cells, may be seen as the marrow is displaced and stressed.

Common causes include primary marrow fibrotic disorders such as myelofibrosis, metastatic involvement of the bone marrow by solid tumors (for example breast or prostate cancer), and infiltrative or granulomatous diseases (such as sarcoidosis or tuberculosis). Less commonly, extensive infiltration by hematologic malignancies or granulomatous reactions can produce a myelophthisic process. The result is reduced production of red cells, white cells, and platelets, with compensatory extramedullary hematopoiesis that can cause splenomegaly.

Clinical features often reflect cytopenias: fatigue and pallor from anemia, increased susceptibility to infections from leukopenia, and easy bruising or bleeding from thrombocytopenia. Bone pain and systemic symptoms may occur, and splenomegaly is common due to extramedullary hematopoiesis. Diagnosis relies on laboratory findings (cytopenias, leukoerythroblastic smear) and confirmation by bone marrow biopsy showing replacement of normal marrow architecture by fibrotic or other infiltrative tissue.

Management targets the underlying cause and includes supportive care with transfusions and infection management, along with disease-directed therapies when applicable. Treatments such as antifibrotic agents, systemic therapy for the underlying malignancy, or marrow transplantation may be considered in selected cases. The prognosis depends on the etiology and extent of marrow involvement.