THE HISTOLOGICAL OVERVIEW TO MYELODYSPLASTIC SYNDROMES: EVALUATION OF BONE MARROW SMEARS AND BIOPSIES

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1 Journal of Disease and Global Health 6(3): , 2016 ISSN: International Knowledge Press THE HISTOLOGICAL OVERVIEW TO MYELODYSPLASTIC SYNDROMES: EVALUATION OF BONE MARROW SMEARS AND BIOPSIES YELDA DERE 1*, VOLKAN KARAKUŞ 2, ÖZGÜR ĐLHAN ÇELĐK 1, SERKAN YAŞAR ÇELĐK 1 AND ERDAL KURTOĞLU 3 1 Department of Pathology, Muğla Sıtkı Koçman University, Faculty of Medicine Training and Research Hospital, Muğla, Turkey. 2 Department of Hematology, Muğla Sıtkı Koçman University, Training and Research Hospital, Muğla, Turkey. 3 Department of Hematology, Antalya Ataturk Training and Research Hospital, Antalya, Turkey. AUTHORS CONTRIBUTIONS This work was carried out in collaboration between all authors. Authors YD, VK and OIC designed the study, wrote the protocol and interpreted the data. Authors YD and VK anchored the field study, gathered the initial data and performed preliminary data analysis. Authors SYC and EK managed the literature searches and produced the initial draft. All authors read and approved the final manuscript. Received: 12 th November 2015 Accepted: 8 th December 2015 Published: 17 th December 2015 Original Research Article ABSTRACT Objectıve: Myelodysplastic syndromes (MDS) are clonal haematopoietic stem cell diseases characterized by one/multilineage cytopenias and dysplasia in one or more of cell lineages. The common pathological manifestations of dysplasia are nuclear fragments and multinuclearity of erythroid cells, hypogranulation/ hyposegmentation of the granulocytes, and micromegakaryocytes. We aimed to group the dysplastic features in MDS to organize a useful,schematic approach for pathologists to achieve the accurate diagnosis. Methods: The demographical and histomorphological features of BM aspirates and BM biopsies of 40 MDS cases diagnosed according to WHO criteria were revised and regrouped. The cellularity of BM biopsy and the percentage of blasts in aspirates and biopsies, confirmed by CD34 immunostaining, were compared and noted. Results: Twenty two female (55%) and 18 male (45%) patients with a mean age of were included. The mean cellularity of biopsies was 49.2%. The highest dysplastic lineage was erythroid lineage (75%, n:30) in aspirates and the most common dysplastic features were nuclear abnormalities and binuclear erythroid cells. However, megacaryocytic lineage was the highest dysplastic lineage in biopsies (70%, n:28) and the most common dysplastic feature was found as hypolobulation/ monolobulation. The mean percentage of blastic cells was 2.55 in aspirates and 3.62 in biopsies. Conclusıon: The most common dysplastic lineages and features should be remembered and investigated on every BM aspirate and biopsy by every hematologist and hematopathologist in order to reach an accurate diagnosis of MDS. Keywords: Dysmegakaryopoesis; diserytropoesis; disgranulopoesis; myelodysplastic syndrome; CD34. *Corresponding author: yeldamorgul@gmail.com, yeldadere@mu.edu.tr;

2 1. INTRODUCTION MDS are a group of hematopoietic neoplasms which are being classified according to cytogenetic and morphologic features [1]. The most common presentation of MDS is cytopenias of different lineages [2,3]. The diagnostic approach for MDS is composed of cytologic evaluation of bone marrow (BM) smears, BM biopsies and karyotype analysis [4,5]. The most important role of histopathology in MDS is differentiating from other diseases mimicking MDS such as leukemic infiltrations especially acute myeloid leukemia (AML), hairy cell leukemia or systemic mastocytosis [3]. Among many criteria, the presence of hematopoetic cells with abnormal morphology and localization in addition to the minimally increased (2-3%) number of progenitor / precursor cells showing CD34 positivity remains the most important ones supporting diagnosis of MDS [3]. The BM smears or biopsies are the only was of morphologic examination of hematopoetic cells. The determination of blastic cell percentage is another important step of diagnosis in MDS because of the strict limits of blastic cells in subgroups of MDS, refractory anemia excess blast and in AML. Thus, immunohistochemical analysis, especially anti-cd34 and anti-cd117, is almost always needed to evaluate the blastic cell percentage in MDS. In this study, we aimed to put forth the most common dysplastic features of our MDS patients seen in BM smears and biopsies in addition to the blastic cell percentages evaluated by immunohistochemistry of anti-cd MATERIALS AND METHODS This is a retrospective study of 40 patients diagnosed with MDS between July 2014 and March 2015 in Muğla Sıtkı Koçman University Training and Research Hospital. Bone marrow biopsy was performed by the same hematologist on patients with Hb <11 mg/dl, PLT< X10 9 /mm 3, PNL < 1500/mm 3 for over 6 months with a preliminary diagnosis of suspicious for MDS. These cases were evaluated by bone marrow smears and bone marrow biopsy. Bone marrow smears were observed by both hematologist and hematopathologist. The bone marrow biopsy was evaluated by routine pathologic examination in addition to the automated immunohistochemical procedure of CD 34 staining. Cases were all then established according to WHO criteria [1] for diagnosis. Dysplasia was defined when seen in >10% of the cells. Patients were accepted as sideroblastic when sideroblasts were observed over %15. MDS cases were diagnosed according to the WHO criteria [1] Patients transformed to AML and KMML were excluded from the study. Demographic data of the cases were obtained from hospital records. The pathology reports and hematoxylen eosin slides of all cases were revised in case of the missing data. All cases were already stained with CD34 antibody by automated immunohistochemical staining with Leica Bond Max. The antibodies used for staining were CD34 (Leica ). The cellularity of BM biopsies were noted and the average cellularity was calculated in addition to the minimum and maximum levels. The dysplastic features were subgrouped if they were seen in BM smears or in biopsies for determining the most common dysplastic features seen in each group. Also, if detected, the hyperplastic lineage was noted. The slides were immunohistochemically stained by Leica Bond-Max automated system using anti-cd34 (Novocastra Liquid Mouse Monoclonal Antibody) antibody and observed under Olympus BX46 microscope. Then, the blastic cell percentage was counted excluding CD34 (+) endothelial cells. Descriptive statistics, frequencies and Chi-Square tests for non parametric correlations were used in statistical analysis of the data by SPSS 15.0 Package Programme for Windows. 3. RESULTS Among 40 patients with a mean age of 69.17; 22 were female whilst 18 were male. The average cellularity of the biopsies was 49.20% with a minimum of 20% and a maximum of 80% (Fig. 1). In the 57,5% (n:23) of the cases erythroid hyperplasia was found in addition to that megakaryocytic hyperplasia was observed in 37,5% (n:15) and myeloid hyperplasia in 10% (n:4) of the cases. The most common dysplastic lineage was erythroid followed by megakaryocytic and myeloid lineages. Cases with triple lineage dysplasia forms 32,5%(n:13) of all. In the bone marrow smears, the most common dysplastic features can be counted as nuclear irregularities in erythroid cells (55%) (n:22) (Fig. 2a), followed by hypogranulation (27,5%) (n:11) and hypersegmentation (25%) (n:10) in myeloid cells (Fig. 2b). Ringed sideroblasts were observed in 15% of the cases. The megakaryocytic lineage was dysplastic in most of the cases (70%) (n:28) showing hypolobulated and hyperchromatic megakaryocytes 103

3 (40%) (n:16) and micromegakaryocytes (10%) (n:4) as the most common dysplastic forms of megakaryocytic lineage (Figs. 3a and 3b). Atypic localization of immature precursors (ALIP) was seen in only 3 cases (7,5%). These 3 cases also showed high blastic cell counts as 6%, 8% and 10% concordant with RAEB. In BM smears the average percentage of blastic cells was 2,55%. In biopsies the average of progenitor / precursor cells with CD34 (+) was found as 2.62%. Six cases showed a rate of CD34 positive progentior/precursor cells over 4% and accepted as compatible with refractory anemia excess blasts (RAEB). Fig. 1. Hypercellular bone marrow with 90% cellularity, HE, X200 Fig. 2. Dyserythropoesis characterized with nuclear irregularities (2a and 2b), bone marrow smear, Giemsa, X400. Dysgranulopoesis with hypersegmentation (2b, arrow), bone marrow smear, Giemsa, X400 Fig. 3. Dysmegakaryopoesis with hyperchromatic and small megakaryocytes, bone marrow biopsy, HE, X200 (3a), bone marrow smear, HE, X400 (3b) 104

4 4. DISCUSSION The diagnosis of MDS depends on morphological evaluation of BM cells which can be applied with BM smears, BM biopsies in addition to karyotypic analysis [4,5]. BM smears can be observed by hematologists and pathologists however BM biopsy is one of the most important material because it can be stored as paraffine blocks and additional analysis can be made on these biopsies [1]. The evaluation of BM biopsy on MDS cases is a multi-step approach beginning with the assessment of the cellularity. The cellularity can be assessed only by BM biopsy so that in hypoplastic MDS cases the evaluation of the cellularity in biopsy gets more important because of the inefficient BM smears [6]. The BM cellularity is generally subgouped as hypocellular, normocellular and hypercellular. The limits of cellularity were reported different in the literature however cellularity usually can be grouped as <20% as hypocellular, 20-70% as normocellular and over 70% as hypercellular in adults however the age of the patient is one of the most important factors effecting BM cellularity [7,8]. According to these criteria, hypocellularity is seen in 10-20% of MDS cases [9]. Our cases mostly were normocellular with an average of 49.20%. Among them, only two cases (5%) were hypocellular. The second step is the evaluation of morphological characteristics of dysplasia and to assess the dysplastic lineages. The morphological abnormalities supporting the diagnosis of MDS can be counted as multinuclearity of the erythroblasts, chromatin bridging, ringed sideroblasts, pseudo-pelger neutrophils, hypogranulated or agranulated neutrophils, micromegakaryocytes, binuclear or hyperchromatic megakaryocytes according to the report of International Working Group on Morphology of MDS [10]. Dysplastic features of different lineages can be observed in both smears and biopsies. However, dyserythropoiesis is generally observed in smears and dysplasia in other lineages in both smears and biopsies [1]. The common characteristics of erithyroid dysplasia are nuclear fragmentation, megaloblastoid changes, nuclear irregularities, chromatin bridging. Among our cases the most common dyserythropoetic features were nuclear irregularities and multinuclearity. Xiong et al. [11] also reported that the dysplastic features in mature erythrocytes such as poikilocytosis and gigantocytes were concordant with the diagnosis of MDS however the accurate value of these features remain unclear. In myeloid cells the major dysplastic features were hypogranulation and hypersegmentation. A specialized form of hypolobulation, Pseudo-Pelger neutrophils is one of the most important features especially in cases showing transformation to AML however this may also can be seen due to many different reasons like transplantation drugs or other medications [12]. In our cases the most common abnormalities of myeloid cells were also hypogranulation and hypersegmentation. Abnormal localized immature precursors, ALIP, defined as small clusters of immature cells located in the central marrow places rather than paratrabecular region and originated from the precursors of all the lineages shows a significant relation to cases with high risk of AML [9]. We observed this in 3 of the cases and these cases showed high rates of blastic cells. The megakaryocytic lineage is the most easily defined precursor cell group due to the larger size of the cells. Abnormal megakaryocytes are usually seen as micromegakaryocytes generally associated with isole del 5q MDS in addition to mononuclear and hyperchromatic forms [9,13]. We observed dysmegakaryopoiesis in 28 cases (70%) and the most common dysplastic features were hypolobulation and hyperchromasia seen in 16 cases (40%). The immunohistochemistry is an easy way to define the percentage of progenitor/precursor cells showing CD34 positivity in MDS [3]. Also this process helps to specify the presence of ALIP, the subgroups of MDS, the high risk MDS patients and transformations to AML. The most important step of detecting the real percentage of CD34 positive progenitor / precursor cells is the exclusion of CD34 positive endothelial cells [3]. We detected CD34 positive progenitor / precursor cells with an average of 2.62% in our cases with only six cases over 4%. The accurate diagnosis of MDS depends on morphological evaluation of hematopoetic cells in addition to specific genetic studies. However it it important to remember that these dysplastic features should be observed in >10% of the cells for accepting as real dysplasia [14]. 5. CONCLUSION Additional studies for BM biopsies especially immunohistochemical detection of CD34 positive progenitor/precursor cells is a major step of the evaluation of these cases. Therefore, a combined evaluation of bone marrow smears, biopsies and genetic studies were needed to make an accurate diagnosis of MDS. 105

5 CONSENT All authors declare that written informed consent was obtained from the patient (or other approved parties) for publication of this case report and accompanying images. ETHICAL APPROVAL All authors hereby declare that all experiments have been examined and approved by the appropriate ethics committee and have therefore been performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki. COMPETING INTERESTS Authors have declared that no competing interests exist. REFERENCES 1. Brunning RD, Bennett JM, Flandrin G. Myelodysplastic syndromes; in Jaffe ES, Harris NL, Stein H, Vardiman JW (eds): World Health Organization Classification of Tumours. Pathology and genetics of tumors of hematopoietic and lymphoid tissues. Lyon, IARC. 2001;1: Bennett JM, Catovsky D, Daniel MT, Flandrin G, Galton DA, Gralnick HR, et al. Proposals for the classification of the myelodysplastic syndromes. Br J Haematol. 1982;51: Horny HP, Sotlar K, Valent P. Diagnostic value of histology and immunohistochemistry in myelodysplastic syndromes. Leuk Res. 2007;31: Bennett JM. A comparative review of classification systems in myelodysplastic syndromes (MDS). Semin Oncol. 2005;32: Greenberg P, Cox C, LeBeau MM, Fenaux P, Morel P, Sanz G, et al. International scoring system for evaluating prognosis in myelodysplastic syndromes. Blood. 1997;89: Lambertenghi-Deliliers G, Annaloro C, Oriani A, Soligo D. Myelodysplastic syndrome associated with bone marrow fibrosis. Leuk Lymphoma. 1992;8: Hartsock RJ, Smıth EB, Petty CS. Normal variations with aging of the amount of hematopoietic tissue in bone marrow from the anterior iliac crest. A study made from 177 cases of sudden death examined by necropsy. Am J Clin Pathol. 1965;43: Tuzuner N, Cox C, Rowe JM, Bennett JM. Bone marrow cellularity in myeloid stem cell disorders: Đmpact of age correction. Leuk Res. 1994;18(8): Brunning RD, Germing U: Myelodysplastic syndromes; in Attilio Orazi, Lawrence M Weiss, Kathy Foucar, Daniel M Knowles, (ed). Neoplastic hematopathology. Wolters Kluwer Lippincott Williams & Wilkins 3 rd Edition. 2013; Mufti GJ, Bennett JM, Goasguen J, Bain BJ, Baumann I, Brunning R, et al. Diagnosis and classification of myelodysplastic syndrome: International working group on morphology of myelodysplastic syndrome (IWGM-MDS) consensus proposals for the definition and enumeration of myeloblasts and ring sideroblasts. Haematologica. 2008;93: Xiong B, Tang ZH, Zou P, Qing F, Yue QF, Chen WX, Liu XY. Dysplasia features of myelodysplastic syndrome in ethnically chinese people. Acta Haematol. 2014;131: Wang E, Boswell E, Siddigi I, Lu CM, Sebastian S, Rehder C, et al. Pseudo-Pelger Huët anomaly induced by medications. A clinicopathologic study in comparison with myelodysplastic syndrome-related Pseudo- Pelger Huët anomaly. Am J Clin Pathol. 2011; 135: Mathew P, Tefferi A, Dewald GW, Goldberg SL, Su J, Hoagland HC et al. The 5qsyndrome: A single-institution study of 43 consecutive patients. Blood. 1993;81(4): Camitta BM, Rappeport JM, Parkman R, Nathan DG. Selection of patients for bone marrow transplantation in severe aplastic anemia. Blood. 1975;45: Copyright International Knowledge Press. All rights reserved. 106