Discovering a high percentage of blast cells in bone marrow can be an alarming finding. The bone marrow, a spongy tissue found within certain bones, produces all blood cells, including red blood cells, white blood cells, and platelets. A significant elevation in the number of immature blood cells, known as blast cells, is a serious medical indicator that requires prompt evaluation and understanding.
Understanding Blast Cells
Blast cells are the earliest, most immature forms of blood cells, precursors to all mature blood cells. In a healthy individual, these cells reside primarily within the bone marrow, where they mature. They differentiate into various specialized blood cells, including red blood cells, white blood cells, and platelets. Normally, blast cells constitute less than 5% of cells in healthy adult bone marrow.
A minimal presence of these immature cells is natural. When mature blood cells are needed, these blasts develop and are then released into the bloodstream to perform their functions. However, a dramatically increased percentage of blast cells, such as 90%, indicates an uncontrolled and abnormal proliferation of these immature cells. These blasts fail to mature correctly, meaning they cannot perform the functions of healthy blood cells, leading to a severe imbalance.
The Critical Meaning of 90 Percent
A bone marrow finding of 90% blast cells strongly suggests acute leukemia. The World Health Organization (WHO) classifies acute leukemia when blast cells constitute 20% or more of cells in the bone marrow or peripheral blood. A 90% blast count is a definitive indicator of acute leukemia, such as acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL).
This high percentage signifies a rapid, uncontrolled growth of cancerous, immature blood cells that overwhelm the bone marrow. The abnormal cells crowd out healthy stem cells, preventing the production of functional blood cells. This leads to symptoms like anemia, increased susceptibility to infections, and easy bruising or bleeding. The urgency stems from the aggressive nature of acute leukemias, which can progress quickly.
Confirming the Diagnosis
Once a high blast cell count is suspected, the diagnostic process involves specialized procedures to confirm the presence and specific type of leukemia. An initial finding often comes from a bone marrow biopsy and aspiration, which assess the bone marrow’s cellular composition. During these procedures, a sample of fluid (aspiration) and solid tissue (biopsy) is collected from the hip bone for microscopic examination.
Further tests classify the leukemia, guiding treatment decisions. Flow cytometry identifies and counts blast cells, determines their lineage (myeloid or lymphoid), and detects specific markers on their surface. Cytogenetic testing examines chromosomes within the cells for structural or numerical abnormalities, providing insights into the disease’s genetic makeup. Molecular testing analyzes specific gene mutations, which helps refine the diagnosis and predict how the disease might behave, informing a personalized treatment plan.
Overview of Treatment
Treatment for acute leukemias is aggressive and initiated quickly. The primary goal of therapy is to eliminate cancerous blast cells and restore normal blood cell production in the bone marrow. Chemotherapy is a foundational treatment approach, using anti-cancer drugs that destroy leukemia cells. These drugs target rapidly dividing cells, including blast cells.
In some cases, after high-dose chemotherapy, a stem cell transplant may be considered. This procedure replaces the patient’s diseased bone marrow with healthy blood-forming stem cells. Targeted therapies and immunotherapies represent newer approaches that harness the body’s immune system to fight cancer. The treatment plan is individualized, considering the type of leukemia, patient’s age, overall health, and genetic factors.