Bone Marrow Hyperplasia in Elderly Acute Lymphoblastic Leukemia Changed From Low Into Hyperactive: a Case Report

Bin Zhang (  zhangb2021cn@126.com ) the rst a liated hospital of hebei north university Yan-Xia Cai the rst a liated hospital of hebei north university Xia Wang the rst a liated hospital of hebei north university Xun-Tao Liu the rst a liated hospital of hebei north university Sheng-Chun Fang the rst a liated hospital of hebei north university Su-Zhen Zhang the rst a liated hospital of hebei north university Fei Zhao the rst a liated hospital of hebei north university Di-Yuan Guo the rst a liated hospital of hebei north university Li-Na Geng the rst a liated hospital of hebei north university


Background
Bone marrow hypoplasia is mainly seen in acute arrest of hemopoiesis and in aplastic anemia [1].
Aplastic anemia is a hematopoietic function failure syndrome caused by many potential factors, and is characterized by lack of hematoblasts in the bone marrow and the reduced peripheral blood cells, and its clinical manifestations include anemia, hemorrhage and infection [2]. Although its pathogenesis is not fully understood, but aplastic anemia is con rmed to be related to chemicals, radiation, virus infection and genetic factors [2]. It has two peak periods of incidence, i.e., 15-25 years of age and > 60 years of age [2]. According to the extent of bone marrow failure and the progression of clinical symptoms, it can be categorized as sever and non-severe, or acute and chronic [3].
Lymphocytic leukemia is a clonal malignant disease originate from lymphocytes, with an incidence rate of 2.7/100, 000 [4]. It has a rapid onset, and clinical symptoms are related to the hyperplasia and in ltration of lymphocytes, especially in elderly patients, whose immune functions are worse and thus prognosis is bad [5]. The manifestations of bone marrow include extreme hyperplasia, and is mainly comprised of primitive cells, which is different from aplastic anemia and can be used to distinguish it from aplastic anemia [6]. The percentage of primitive cells should be > 20% in lymphocytic leukemia [6].
However, in clinic, if the main cells are lymphocytes in peripheral blood smear or bone marrow biopsy, it will often be diagnosed as bone marrow hypoplasia or aplastic anemia, especially in morphology tests, due to the darker staining of the cells, the primitive cells are hardly to be distinguished by microscopy [7]. Therefore, we need to nd a better way to accurately diagnose these diseases.
In our recent works, we identi ed a case of B-lymphocytic leukemia, which was rstly though to be aplastic anemia based on morphology results at two different locations but was evolved to extremely hyperplasia after 50 days. We hope that this report can provide evidence and suggestions for the accurate diagnosis of these diseases.

Clinical manifestations of the patient
The current study has been approved by the Ethics Committee of our hospital, and the patientd signed written informed consent.
The patient was female and aged 71. Her main complaints were fatigue, short breath and inappetence.
Physical examinations showed anemic appearance, apparent sternal tenderness, but without stained yellow or hemorrhagic spot in her skin or mucosa. There was an enlarged, rm lymph node in the right neck sized about 1*1 cm, with the absence of tenderness and a low mobility. No other lymph nodes were detected.

Lab equipment and reagents
Blood routine tests were done in XN3000 blood cell counter (SYSMEX, Japan).

Peripheral blood cells
As shown in Fig. 1, from the rst test on Jan.26, 2018 to the last test on Mar.7, 2018, peripheral white blood cells (WBC), red blood cells (RBC), hemoglobin (HGB) and platelet (PLT) increase to normal level, meanwhile lymphocytes percentage decreased to normal, and segmented neutrocyte percentage increased to normal, while there was no change in monocyte percentage (Table 1). The smear of peripheral blood cells was done on Jan.27, 2018, which showed that segmented neutrocytes accounted for 8%, and mature lymphocytes accounted for 86%, atypical lymphocytes accounted for 6%, and there were few platelets, and there were 8 nucleated red blood cells (NRBC). Figure 1A is the rst bone marrow smear result done Jan.27, 2018. It shows bone marrow hypoplasia, and mature lymphocytes accounted for 96%, segmented neutrocytes accounted for 1%, NRBC accounted for 3%. There was no megakaryocyte and there were few platelets. Figure 1B is the second bone marrow smear result done Feb.5, 2018. It still shows bone marrow hypoplasia. Mature lymphocytes accounted for 39% (suspected juvenile cells in the entire smear sample were 0.5%), neutrophilic myelocytes accounted for 1.5%, neutrophilic metamyelocytes accounted for 1.5%, band neutrophils accounted for 1.5%, segmented neutrocytes accounted for 34%, NRBC accounted for 21%. There was one megakaryocyte and there were few platelets. Figure 1C is the third bone marrow smear result done Mar.7, 2018. It shows extremely hyperplasia of the bone marrow. primitive lymphocytes accounted for 87%, mature lymphocytes accounted for 4%, neutrophilic metamyelocytes accounted for 0.5%, band neutrophils accounted for 0.5%, segmented neutrocytes accounted for 0.5%, NRBC accounted for 7%. There were 56 megakaryocyte and there were few platelets. Figure 1D is the POX staining which shows negative.

Smear result and genetic result of bone marrow
Genetic results show that it was BCR/ABL (P210) fusion gene positive.

Bone marrow biopsy
As shown in Fig. 2A

Treatment and outcomes
COP chemotherapy regimen was adopted, which included cyclophosphamide (0.8 g at day 1), vincristine (2 mg at day 1), prednisone (60 mg from day 1 to day 7). During the chemotherapy, peripheral blood cells decreased, as WBC was 0.9×109/L, PLT was 0-2.0×109/L, and HGB was 59-67 g/L. Suspended red blood cells and platelets were infused, but no signi cant effects. At the last day of chemotherapy, infection occurred, which was not relieved even after a week of anti-infection of high generation antibiotics. Heart failure also occurred. The patient's family decided to stop treatment. Prognosis was poor, which was in accordance with the literature [3]. The diagnosis of aplastic anemia should include decrease of all peripheral blood cells, bone marrow hypoplasia, and should also exclude other disease that can cause decreased peripheral blood cells (e.g., paroxysmal nocturnal hemoglobinuria, myelodysplastic syndrome, myelo brosis, etc.), and the main cell type should he lymphocytes [11][12][13]. But there's no clear guidance on the number of juvenile cells, especially in bone marrow hypoplasia, and there's no requirement to include the number of nucleated cells, which could result in misdiagnosis. In the current study, we performed bone marrow punctures at two different locations, and also conducted multiple smear sample reading, and found that there were 0.5% suspicious juvenile cells. Therefore, we suggest to examine the entire smear sample, and if suspicious juvenile cells are found, further examinations and consultations should be done.

Discussion
Acute lymphocytic leukemia, on the other hand, is a clonal malignant disease originate from lymphocytes, with extremely hyperplasia of the bone marrow and mainly comprised of primitive cells, making it very different from aplastic anemia in bone marrow smear. In the current study, bone marrow smear results of the patient in the rst two tests reached the diagnostic criteria of lymphocytic leukemia. Therefore, in patients with bone marrow hypoplasia, bone marrow smear should be performed, and if suspicious juvenile cells are found, we should follow up in the following time period, and ow cytometry as well as bone marrow biopsy should be done, especially immunological types should be determined by detecting the antigens, which can provide supplemental evidence for the diagnosis [14][15][16][17][18].
By analyzing the rst ow cytometry results, we found that juvenile cells accounted for 0.69%, which could be easily ignored during clinical diagnosis. The other results of this ow cytometry were in accordance with the juvenile cells. In the second test, we found that CD45percp became negative, which showed that maturity of this kind of lymphocytes were very low, and was different from most lymphoblasts and prolymphocytes. The other results further proved that this cell type was early-stage primitive cells, especially because CD34 was the symbol of hematopoietic stem cell [19][20]. Meanwhile, the high expression of CD10 showed that these lymphocytes originated from the germinal center.

Conclusions
For patients whose hypoplastic bone marrow suddenly became extremely hyperplasia, morphology was not very useful, thus de nite diagnosis must be dependent on immunological types and bone marrow biopsy results. The current study has been approved by the Ethics Committee of The First A liated Hospital of Hebei North University, and the patientd signed written informed consent.

Consent for publication
Not applicable.

Availability of data and materials
The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Con ict of Interest Statement
The authors have no con icts of interest to declare.

Author Contributions
Substantial contributions to the conception or design of the work ZB,CY,WX Acquisition, analysis, or interpretation of data for the work LX,FS,ZS Drafting the work or revising it critically for important intellectual content ZF,GD,GL Final approval of the version to be published All Authors Figure 1 A. The rst bone marrow smear result. It shows that mature lymphocytes (wright stain×1000) were regularly shaped, with little and bright blue cytoplasm, densi cated chromatin and regular cell nucleus, no nucleolus was seen. B. The second bone marrow smear result. It shows the rarely seen suspicious juvenile cells (wright stain×1000), whose shape was regular and slightly large, with little and bright blue cytoplasm, loosen chromatin and regular cell nucleus, no nucleolus was seen. C. The third bone marrow smear result. It shows very active juvenile cells, whose shape was regular and slightly large, with little and bright blue cytoplasm, loosen chromatin and regular cell nucleus, and also had obvious nucleolus. C. POX staining in the third bone marrow smear, which was negative.

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