A 65-year old male is seen by his physician for splenomegaly…

A 65-year old male is seen by his physician for splenomegaly, abdominal discomfort, mild lymphadenopathy, and recurrent infections.  Peripheral blood reveals a pancytopenia with large lymphocytes that have an oval to kidney-shaped nucleus.  The cytoplasm is pale blue with poorly defined borders and appear to have threadlike projections.  These cells were tested using flow cytometry and found to be positive for CD19, CD20, and CD21.  The cells were found to be acid phosphatase positive.  The color of the stain remained after the addition of L-tartrate.  These results are most indicative of which of the following?