marrowinfiltrating

Marrow-infiltrating, or marrow infiltration, is a descriptive term used in hematology and oncology to describe the replacement or extensive occupation of the bone marrow by abnormal cells or tissue rather than by normal hematopoietic elements. It can occur in a variety of diseases and is often associated with marrow failure or cytopenias.

Common causes include hematologic malignancies such as acute and chronic leukemias, lymphomas with marrow involvement, and plasma cell disorders like multiple myeloma. Metastatic solid tumors (for example, breast, prostate, and lung cancers) can also infiltrate the marrow. Other infiltrative conditions include myelofibrosis, granulomatous diseases, and certain rare histiocytic disorders.

Pathology may be described as diffuse, nodular, or interstitial infiltration of the marrow by malignant cells or fibrous tissue. Diagnosis typically requires a bone marrow biopsy with morphological assessment, and is often supplemented by flow cytometry, immunohistochemistry, cytogenetics, and molecular testing to identify the underlying disease.

Clinically, marrow infiltration can cause pancytopenia or cytopenias, leading to fatigue, infections, and bleeding. Other symptoms depend on the underlying condition and may include bone pain or organomegaly.

Management focuses on treating the underlying disease when possible, with supportive care such as transfusions, antibiotics for infections, growth factors, and, in eligible cases, stem cell transplantation. Prognosis varies widely by etiology and disease stage; marrow involvement generally indicates advanced disease and higher risk of complications.