CML-006 CML Blastic Crisis Diagnosis Based on a Lymph Node Biopsy in an Egyptian Male Patient: A Rare Case Report

Abstract

Chronic myeloid leukemia (CML) is a clonal myeloproliferative triphasic clinical disorder characterized by a distinct genetic abnormality: the BCR-ABL fusion gene (Philadelphia chromosome). The presence of blasts in the lymph node (LN) is enough for a diagnosis of blast-phase CML. The case study herein is a very rare presentation. A case report of a 53-year-old Egyptian male patient who presented in 2020 with night fever and sweats. Oncology Center Mansoura University. Examination revealed firm, non-tender, generalized cervical and bilateral axillary lymphadenopathy. The patient's abdominal examination revealed moderate, firm, and non-tender splenomegaly. Complete blood count: white blood cell count 239 k/µL, normocytic normochromic anemia with hemoglobin 11 g/dL, and platelet count 321 k/µL. Differential leukocyte count revealed blasts (1%), myelocytes (12%), metamyelocytes (25%), polymorphonuclear leukocytes (50%), eosinophils (2%), basophils (3%), and lymphocytes (2%). Bone marrow (BM) examination was hypercellular; 70% of the total BM cellularity was replaced by myeloid series highlighted by myeloperoxidase, and few blasts (<1%) were CD34+, suggesting chronic-phase CML. BCR-ABL1 gene rearrangement by Q RT-PCR was 65.9% IS. The patient started imatinib 400 mg/d. LNs were suspicious, and excisional biopsy showed multiple fatty nodules -3.5×3 cm; the cut section was firm, grayish white, partially effaced, and replaced by infiltrate of myeloid series (MPO+, CD3-, CD30-, and CD79a) with a high Ki67 proliferation index. LN infiltration suggested a CML blastic crisis despite the fact that repeated BM aspirate samples revealed no increase in blasts. However, the new BM biopsy (BMB) revealed that most of the cellularity was replaced by myeloid series with CD117+ (15%) and CD34+. Acute leukemia risk assessment revealed FLT3- and inv(16)+, and FISH analysis indicated t(9:22). The patient was refractory to ICT and imatinib and was shifted to salvage. Complete remission was confirmed by PET/CT scan and BMB; however, he did not achieve a molecular response (Q RT-PCR for BCR-ABL1 15% IS). He was switched to dasatinib with consolidation chemotherapy, and HLA matching was done for results. This case report highlights the importance of a rare CML presentation with extramedullary infiltrates. A myeloid sarcoma should be excluded before setting the treatment plan.