CLL Summary
Epidemiology: CLL is the most prevalent adult leukemia in the western countries. It is more common in men than in women (ratio 1.7 to 1). There is no known risk factors for CLL. Median age at diagnosis between 67 and 72 years. Diagnosis: Sustained increase in mature appearing lymphocytes in the peripheral blood to more than 5,000/mm3. The majority of cases are B-CLL. IHC stains: CD5, low density expression of surface Ig, CD20 & CD22 unlike mantle cell lymphomas which has higher expression of CD20 and surface Ig. The bone marrow usually is infiltrated by at least 30% lymphocytes. Although a bone marrow biopsy is not needed to make the diagnosis, they are strongly recommended if cytopenias in other cell lines are present before starting therapy. Cytogenetic and molecular abnormalities Conventional techniques identify cytogenetic abnormalities in 50% of cases. FISH allows for identification of cytogenetic abnormalities in > 80% of cases