Background

CD5 negative chronic lymphocytic leukemia (CD5- CLL) is one such subtype of atypical CLL. With the patient’s informed consent, we present a challenging case of CD5-/CD10- atypical CLL with immune-thrombocytopenia.

Case Discussion

A 78-year-old male presenting to our clinic for evaluation of monoclonal B-cell lymphocytosis. The physical exam included no organomegaly; the clinical findings and imaging were benign. Bone marrow biopsy was normocellular with orderly trilineage hematopoiesis with 10-15% monoclonal B-cell infiltrates. Flow cytometry showed +CD19, +CD20, and -CD5, -CD10, -CD23, -CD38, -BCL2, and -CD11c. A molecular study detected a TP53 mutation, but no BRAF mutation was detected. A provisional diagnosis of B-cell lymphoma/leukemia with prominent nucleoli (SBLPN). The patient was referred to a tertiary care center. Additional testing included a PET scan with 3.4 cm FDG uptake in the right frontal calvarium. CD103 was negative. The fluorescence in-situ hybridization showed del17p in 73%, del14q in 12%, yet it was negative for trisomy 12, IgH-bcl-1, bcl-6, c-myc, IgH-bcl-2, Del 11q23, Del 13q14.3. Diagnosis of SBLPN was rejected in favor of Atypical CLL due to the lack of CD103 and CD11c markers. Splenic marginal zone leukemia was rejected given the negative splenomegaly on imaging.

Conclusion

In our patient, the final stage was Rai 0 with platelet count recovery subsequent to C1 of dexamethasone and rituximab for CLL associated ITP. We opt for treatment of our patient with BTKi when warranted, consistent with current guidelines. Review of literature highlights debated prognostic implications. As CD5 immunophenotyping is a requirement for diagnosis by the ISS/WHO, as well as the implication of CD5 in the pathogenesis of MBL-CLL, the CD5 negativity would suggest the possibility of a separate entity altogether. Finally, the implications of CD5 negativity on the risk for Ritcher’s transformation remains unexplored.


The patient provided informed consent.

HCA Healthcare Disclaimer

This research was supported in part by HCA Healthcare and/or an HCA Healthcare affiliated entity. The views expressed in this publication represent those of the author(s) and do not necessarily represent the official views of HCA Healthcare or any of its affiliated entities.