Fast Five Quiz: Chronic Lymphocytic Leukemia Differential Diagnosis

Karl J. D'Silva, MD


March 09, 2020

The differential diagnosis of CLL includes prolymphocytic leukemia, which has a typical phenotype that is positive for CD19, CD20, and surface membrane immunoglobulin; one half will be negative for CD5. A peripheral smear of a patient with CLL often reveals large atypical cells, cleaved cells, and prolymphocytes, which may account for up to 55% of peripheral lymphocytes. When this percentage is exceeded, however, prolymphocytic leukemia (B-cell PLL) is a more likely diagnosis.

CD5 and CD21 negativity are typical of hairy cell leukemia, as is moderate positivity for surface membrane immunoglobulins of multiple heavy-chain classes.

The pattern of positivity for CD19, CD20, and CD5 is shared by MCL and CLL; however, MCL cells generally do not express CD23.

Learn more about the differential diagnosis of CLL.


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