A 55-year-old male was admitted to the Department of Hematology of The First Affiliated Hospital of Guangzhou University of Chinese Medicine because of atony of both lower extremities and malaise for more than 6 months. The patient reported increased fatigue and thirst during the last 2 months and described perspiring during sleep. He also had an associated weight loss of 5 kg during 6 months, and fever. Physical examination revealed splenomegaly.
Laboratory examination of peripheral blood showed hyperleukocytosis with white blood cell (WBC) counts of 38.22 x 109/l and a platelet (PLT) counts of 390 x 109/l, and serum biochemical analysis showed lactate dehydrogenase (LDH) levels of 1122 U/l. Morphological examination of bone marrow (BM) aspirate showed a thrombocytosis and hypercellular marrow with high degree of dysgranulopoiesis, including 0.5% myeloblasts, 3.5% promyelocytes, 9% myelocytes, 3% metamyelocytes, 10% eosinophils, 4.5% lymphocyte, 2% nucleated red blood cells, and 9.5% monocytes (Figure 1). Manual differential count of peripheral blood also revealed a granulocytosis (Figure 2). BM biopsy analysis revealed hypercellular marrow, including neutrophilic leukocytosis to 84% with left shift and immature granulocytes, mean counts of 6-8 megakaryocytes/high power field combined with cell enlargement, and a lack of karyolobism. Immunohistochemical analysis identified myeloperoxidase (MPO)+, CD71+, CD61+, CD117-, and CD34+/- cells. Meshinprotein staining was consistent with grade 1 BM fibrosis (Figure 3). Molecular analyses of BCR/ABL fusion gene was negative and positive for JAK2 V617F. Cytogenetic analysis revealed a normal karyotype (46, XY). A preliminary diagnosis of prefibrotic primary myelofibrosis (pre-PMF) was considered with other myeloid neoplasms needing to be excluded. Next-generation sequencing was performed, and the results identified the JAK2 V617F variant (51% mutations load) along with three additional gene variants, additional sex combs like 1 (ASXL1) G645fs (36.09%), SETBP1 D868N (46.00%), and splicing factor, arginine/serine-rich 2 (SRSF2) P95_R102del (33.56%). Considering the SETBP1 expression, we retested peripheral blood cell morphology and performed a manual differential count that revealed 65% neutrophils, 10% metamyelocyte, 10% myelocytes, 2% promyelocytes, 8% monocytes, 2% basophilic granulocytes, 6% eosinophilic granulocytes, and 3% lymphocytes. Dysgranulopoiesis demonstrated abnormal nuclear segmentation, with 31% neutrophilic granulocyte band forms and 31% nuclear hyper-segmentation. Based on patient medical history, peripheral blood cell morphology, BM pathology, and genetic testing, the most appropriate diagnosis was atypical chronic myeloid leukemia with the coexistence of JAK2, SETBP1, ASXL1, and SRSF2 variants.
Considering the fact that allogeneic HSCT is the only potentially curative treatment for aCML, we recommended HSCT to the patient. However, taking into account the risks and costs of transplantation, the patient refused allogeneic HSCT and opted for treatment with lower risk and minimal pain. According to presence of the JAK2 mutation, a targeted therapy of ruxolitinib combined with symptomatic treatment was recommended since June 2019. For the first 5 months, the therapy consisted of ruxolitinib (40 mg/day). However, there was an aggravation of leukocytosis (from 38.22 g/l to 47.82 g/l), which, combined with the JAK2 mutation, motivated a change in treatment. Since 8 November 2019, Azacytidine (100 mg/day) was added to the treatment protocol daily for 7 days followed by 1x every 30 days. After four courses of therapy, the patient demonstrated a positive response, with effective symptomatic control and small improvement of thrombocythemia (from 368 x 109/l to 208 x 109/l). The most significant evolution was marked reduction in spleen size (thickness from 68 mm to 51 mm; length diameter from 173 mm to 145 mm) and decreased WBC counts from 38.22 x 109/l to 10.79 x 109/l. The JAK2 V617F mutations load dropped from 51% to 44.4%. However, the WBC counts rose again after the fourth course of azacytidine in March this year. A comprehensive follow-up examination on 18 March suggested that white blood cells are 15.54 x 109/l, hemoglobin is 139g/l, and PLT count is 248x 109/l. The results of BM and peripheral blood smears indicate that the granulocyte system is actively proliferating, accounting for 59.5% of nuclear cells. Peripheral blood neutrophil revealed a nucleus left shift, including 7% myelocyte, 6% metagranulocyte, 12% segmented neutrocyte, and 24% band form neutrophilic granulocyte. Eosinophils and basophils are easy to see. BM pathology results revealed that BM fibrosis has progressed to grade 3. Two additional gene mutations of NRAS and KRAS were found through another second-generation sequencing. And the JAK2 V617F mutations load raised to 46.2%. The spleen was more swollen than before, the long diameter increased to 168mm, and the thickness increased to 65mm. The above examination results indicate that the disease has progressed.