Case 4
A 63-year-old male on tacrolimus and mycophenolate mofetil (MMF) for
prior renal transplant was admitted for a several-week history of
episodic fevers. His prior workup, including cultures and serologies for
viral infections, was negative. Pertinent labs at admission: WBC 2.1 x
109/L, Hb 10.2 gm/dL, platelets 60 x
109/L, total bilirubin 0.9 mg/dL, LDH 554 IU/L, ESR 11
mm/hr. Peripheral blood smear showed moderate anisocytosis and normal
WBC and platelet morphology. Bone marrow biopsy showed trilineage
hematopoiesis with occasional large atypical lymphoid cells in small
vessels. Cells were positive for CD20, CD79s, and CD5, and mostly
negative for BCL-2, BCL-6, and CD10. Cytogenetic studies showed abnormal
clones with structural rearrangements of chromosomes 3, 5, 9, 10, and 14
along with loss of 6q. Follow-up random skin biopsies showed rare,
atypical intravascular B cells positive for CD20. EBER was negative. CT
neck, chest, abdomen, and pelvis were negative for lymphadenopathy. CSF
was negative for malignant cells. He received six cycles of R-CHOP with
intrathecal methotrexate with the recovery of counts. MMF was
discontinued at the time of diagnosis. Follow-up PET/CT did not show any
evidence of disease. Post-treatment bone marrow biopsy was negative for
any morphological or immunophenotypic evidence of lymphoma. The patient
continues to be in remission on follow-up.