1. University of Vermont Medical Center
ICCS Case
University of Vermont Medical Center

2. Clinical History
We present the case of a 59-year-old male with a 20-year history of chronic lymphocytic leukemia (CLL)
Presented with weight loss, progressive shortness of breath, and an enlarging supraclavicular lymph node
CBC:
Mild anemia (HGB 11.4 g/dl; MCV 81 fl)
WBC 5,800/cmm with 62% neutrophils, 27% lymphocytes, 9% monocytes, 1% eosinophils, 1% basophils
PLT 100,000/cmm
Biopsy of the supraclavicular lymph node was performed

3. Recommended Analysis Strategy
The following panel was run (Tube 1 and 3 specifically with history of CLL in mind):
Tube 1: CD5 PC5 / CD19 ECD / Kappa FITC / Lambda PE / CD45 PC7
Tube 2: CD7 PC5 / CD3 ECD / CD8 FITC / CD4 PE / CD45 PC7
Tube 3: CD20 PC5 / CD23 ECD / FMC7 FITC / CD10 PE / CD45 PC7

4. Pertinent Findings on Flow Cytometry
The most striking abnormality is a population of lambda-restricted, CD45dim, CD19+, CD5+ cells accounting for the majority (80%) of cells
These cells fall outside of the normal “lymphocyte gate” as defined by CD45 and SS

5. Pertinent Findings on Flow Cytometry
This population is also CD20+(dim), CD10-, FMC7-, CD23+(subset), HLA-DR+, CD22-

6. Pertinent Findings on Flow Cytometry
By forward scatter, the neoplastic cells are large in size
For size comparison, ungated plot showing normal lymphocytes (CD3) vs FS

7. Diagnostic Considerations
Based on flow cytometry results, this case has a classic immunophenotype of CLL (dimCD20, dimCD19, dim surface light chain, CD5+, CD10-, FMC7-, CD23+), and is similar to that seen previously in this patient.
CD200 is also classically + in CLL, though is not used at our institution.
Increased cell size by forward scatter is concerning for a large cell population. Prominent proliferation centers may contribute to higher side scatter in traditional CLL.
Blastic mantle cell lymphoma is a clonal B-cell neoplasm that is CD5+ and CD10- with larger cells, but this would be unusual with this IP pattern coupled with the clinical history.
Morphologic correlation is necessary.

8. Lymph Node Excisional Biopsy

9. Lymph Node Excisional Biopsy
Normal nodal architecture effaced by diffuse population of large cells
Ki67 stain shows high proliferation rate ~60-70%

10. Cytogenetics & FISH
Karyotype: 45,X,-Y,t(8;18)(q24;q22),add(9)(q34)[8]/46,XY[2]
FISH: MYC and BCL6 rearrangements. Normal BCL2.

11. Diagnosis
Diffuse large B-cell lymphoma, transformed from CLL (Richter transformation), with rearrangements in MYC and BCL6 (“double-hit”)

12. Case Discussion
Richter transformation is the development of an aggressive large-cell lymphoma in the setting of underlying CLL
The incidence of Richter transformation has been estimated at 2-9%
Most but not all cases of Richter transformation retain the immunophenotype of the original CLL

13. Take Away Points
We present this case to illustrate that CLL not uncommonly transforms into diffuse large B-cell lymphoma
In a patient with a history of CLL, the immunophenotype alone will not signal transformation, and simple properties of light scatter can be extremely helpful in making the correct diagnosis
Automatic lymphocyte gating may exclude DLBCL populations from analysis, as they often show decreased CD45 expression vs. normal lymphocytes, and careful evaluation is necessary
Clinical history (weight loss, rapidly enlarging lymph node, etc.) can increase level of suspicion

14. References
Kroft SH, Dawson DB, McKenna RW. Large cell lymphoma transformation of chronic lymphocytic leukemia/small lymphocytic lymphoma. Hematopathology. 2001;115:
Parikh SA, Kay NE, Shanafelt TD. How we treat Richter syndrome. Blood. 2014;123:

15. Katherine Devitt
John Lunde
Juli-Anne Gardner
Amanda Chamberlain