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Glioneuronal and neuronal tumors (GNTs) are slow-growing lower-grade neuroepithelial tumors with mature neuronal and, less consistently, glial differentiation. Their identification has relied solely on histological proof of neuronal differentiation, which was considered to represent the well-differentiated nature of GNTs. However, after discovering the genetic alterations in GNTs, particularly those in the MAP-kinase pathway, it became evident that histological diagnoses are not always concurrent with genetic alterations and vice versa. Furthermore, since several inhibitors mediating the MAP-kinase pathway are available, at least for clinical trials, molecular-based classification is now warranted. Thus, the upcoming WHO Classification of Central Nervous System Tumors, 5th edition (WHO5CNS) applied DNA methylation profiling to segregate low-grade neuroepithelial tumors. This review gives an overview of the pathological features of GNTs with particular reference to the newly listed tumor types in WHO5CNS. The knowledge and awareness of each tumor type are essential to make a correct diagnosis and avoid unnecessary radical resection and chemoradiotherapy, as GNTs are relatively indolent and have a prolonged clinical course. In addition, being distinctive in location, age group, and histology, the integration of clinicopathological information will help identify relevant tumor types of GNTs without genetic testing, even in resource-limited settings.
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Glioblastoma is the most common malignant central nervous system (CNS) tumor in adults. Acute common clinical symptoms include headache, seizure, behavior changes, focal neurological deficits, and signs of increased intracranial pressure. The classic MRI finding of glioblastoma is an irregularly shaped, rim-enhancing or ring-enhancing lesion with a central dark area of necrosis. This constellation of features correlates with microscopic findings of tumor necrosis and microvascular proliferation. Besides these common features, several well-recognized histological subtypes include giant cell glioblastoma, granular cell glioblastoma, gliosarcoma, glioblastoma with a primitive neuronal component, small cell glioblastoma, and epithelioid glioblastoma. While glioblastoma was historically classified as isocitrate dehydrogenase (IDH)-wildtype and IDH-mutant groups, the Consortium to Inform Molecular and Practical Approaches to CNS Tumor Taxonomy (cIMPACT-NOW) and the fifth edition of the WHO Classification of Tumors of the Central Nervous System clearly updated the nomenclature to reflect glioblastoma to be compatible with wildtype IDH status only. Therefore, glioblastoma is now defined as “a diffuse, astrocytic glioma that is IDH-wildtype and H3-wildtype and has one or more of the following histological or genetic features: microvascular proliferation, necrosis, Telomerase reverse transcriptase promoter mutation, Epidermal growth factor receptor gene amplification, +7/?10 chromosome copy-number changes (CNS WHO grade 4).”
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@#Pulmonary adenocarcinoma in situ is reclassified as precursor glandular lesions in the fifth edition of WHO classification of thoracic tumours, causing widespread attention and heated debate among domestic thoracic oncologists, radiologists, pathologists and surgeons. We would like to comment on the topic and make a few suggestions on the management of pulmonary nodule during lung cancer screening. We are open to all suggestion and welcome debates.
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La Clasificación de Tumores del Sistema Nervioso Central de la OMS 2016 incorpora biomarcadores moleculares junto a las características histológicas clásicas, en un diagnóstico integrado, con el fin de definir distintas entidades de gliomas con la mayor precisión posible. Los estudios de perfiles moleculares en el genoma han revelado las alteraciones genéticas características y los perfiles epigenéticos asociados con diferentes tipos de gliomas. Estas características moleculares pueden usarse para refinar la clasificación del glioma, mejorar la predicción de los resultados obtenidos con los tratamientos actuales y futuros en los pacientes, y como guía de un tratamiento personalizado. Asimismo, tener una aproximación pronóstica en cada paciente. Este cambio de paradigma ha modificado la forma en que se diagnostica el glioma y sus implicancias en la práctica diaria en la indicación de los diferentes tratamientos al paciente. Aquí, sintéticamente, revisamos y destacamos los biomarcadores moleculares clínicamente relevantes. Intentamos dejar plasmado cómo los avances en la genética molecular de los gliomas pueden promover y allanar el camino hacia la medicina de precisión en neurooncología.
The Classification of Tumors of the Central Nervous System of the WHO 2016 incorporates molecular biomarkers together with the classical histological characteristics, in an integrated diagnosis, in order to define different glioma entities with the highest possible accuracy. Studies of molecular profiles in the genome have revealed characteristic genetic alterations and epigenetic profiles associated with different types of gliomas. These molecular characteristics can be used to refine the classification of gliomas, improve the prediction of the results obtained with current and future treatments in patients and as a guide for a personalized treatment. Also, have a prognostic approach in each patient. This paradigm shift has modified the way glioma is diagnosed and its implications in daily practice in the indication of different treatments to the patient. Here, synthetically, we review and highlight clinically relevant molecular biomarkers. We try to capture how advances in the molecular genetics of gliomas can promote and pave the way to precision medicine in neuro-oncology.
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Humains , Gliome , Marqueurs biologiques , Système nerveux central , Biologie moléculaire , TumeursRésumé
Background: Rabies is one of the commonest zoonotic diseases due to Lyssa virus. Rabies is a 100% fatal disease. Understanding the epidemiological and clinical profile of the victims helps in the prevention of dog bite. But rabies is 100% preventable by pre and post exposure prophylaxis vaccination. Evaluation of side effects of anti-rabies vaccine (ARV) is helpful in the pre and post exposure prophylaxis.Methods: Authors did a descriptive study of 1450 dog-bitten children. Using the pro-forma, authors interviewed the parents, examined the children. Using W.H.O classification, authors classified the dog bite wounds. Anti-rabies vaccination was administered to category 2 dog bite wounded children. Side effects of vaccination are recorded.Results: Out of 1450 children, significantly more number of boys (67%) in the age group of 10-12 years (31%), from class IV socioeconomic category (52%), nuclear families (80%), sustained category III dog bite (52%) in the lower limb (48%) by unvaccinated (82%) stray dogs (60%) while playing or walking (52%) in the street (60%) during night (72%). Purified Vero cell culture rabies vaccine is having rare mild local side effects (2%), rare mild systemic side effects (4.16%) and very rare systemic allergic reaction (0.14%) but no major side effects.Conclusions: Dog bites can be prevented by not allowing the children to play or walk alone in the street especially during night. The severity of wound can be minimized by wearing fully covered extremities. Vaccination of dogs and population control of stray dogs will reduce rabies. There were no major side-effects or adverse events following vaccination (AEFI) with anti-rabies vaccination. Rare mild local side effects and very rare mild systemic side effects may happen.
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Background: The salivary glands are one of the few tissues in the body that are subjected to diverse and heterogeneous range of tumors and tumor like conditions. The relative infrequency of these tumors makes their diagnosis and management quite complicated. Fine needle aspiration cytology (FNAC) is a useful diagnostic procedure which has a recognized role in the evaluation of salivary gland lesions. A pre-operative diagnosis about nature of lesion, whether benign or malignant, will help in making decision about proper management of patient. Aim and Objective: Aim of this study was to know the epidemiology of salivary gland tumors in our region and to evaluate sensitivity, specificity and diagnostic accuracy of fine needle aspiration cytology taking histopathology as the gold standard. Material and Method: It was 3yrs prospective observational study conducted from oct 2015 to oct 2018 in department of pathology KMC/MGM Hospital. Total 59 cases were studied with particular reference to age, sex, site, cytologic details & histological types as per WHO classification. FNAC & histopathological examination was done in all cases came to pathology laboratory . Correlation between cytological & histopathological diagnoses was assessed. Diagnostic accuracy of FNAC was evaluated by comparing cytological & histopathological diagnoses. Results and Discussion : Parotid gland was the most common site of involvement (70% cases). Maximum number of patients was in age range of 41-50 years & male to female ratio was 0.8:1. Most common benign & malignant tumors were pleomorphic adenoma (69.89% cases) & mucoepidermoid carcinoma (8.60% cases) respectively. On cytology, 54 cases while on histopathology 57 cases were diagnosed as neoplastic. Cytological diagnoses correlated with histopathological diagnoses in 94% cases. Sensitivity, specificity & diagnostic accuracy of FNAC were found to be 96.87%, 100% & 96% respectively. Conclusion: FNAC in salivary gland masses is fairly reliable for correct preoperative diagnosis. Multiple sampling and special attention to cytologic features should help to minimize errors
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We reviewed our leukemia database to reclassify 610 patients previously diagnosed as having acute myeloid leukemia (AML) according to the updated 2016 WHO classification. Nine patients were categorized as having myelodysplastic syndrome and myeloid neoplasms with germline predisposition. AML with recurrent genetic abnormalities accounted for 57.4% (345/601) of the patients under the 2016 WHO classification. AML with mutated NPM1 was the most common form (16.5%), with the majority associated with monocytic differentiation (63.6%). AML with double CEBPA mutations accounted for 8.3% of these cases, and the majority were previously diagnosed as AML with/without maturation (78.0%). These newly classified mutations were mutually exclusive without overlapping with other forms of AML with recurrent genetic abnormalities. AML with mutated NPM1 and AML with myelodysplasia-related changes comprised the oldest patients, whereas AML with RUNX1-RUNX1T1 included the youngest patients. The leukocyte count was highest in AML with mutated NPM1, and the percentage of peripheral blood blasts was the highest in AML with double CEBPA mutations. Our results indicate that implementation of the 2016 WHO classification of AML would not pose major difficulties in clinical practice. Hematopathologists should review and prepare genetic tests for the new classification, according to their clinical laboratory conditions.
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Humains , Classification , Leucémies , Leucémie aigüe myéloïde , Numération des leucocytes , Syndromes myélodysplasiquesRésumé
Papillary serous carcinomas of testis are very rare, and only case reports have been reported in the literature. These neoplasms are characterised histologically by papillary fronds and numerous psammoma bodies and exhibit immunoreactivity for markers of ovarian serous carcinomas. These are very aggressive and are both chemo and radioresistant with surgery remained the main stay of management.
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The 2016 WHO diagnostic criteria for chronic myelomonocytic leukemia (CMML) require both absolute and relative monocytosis (≥1×10⁹/L and ≥10% of white blood cell counts) in peripheral blood. Moreover, myeloproliferative neoplasm (MPN) features in bone marrow and/or MPN-associated mutations tend to support MPN with monocytosis rather than CMML. We assessed the impact of the 2016 WHO criteria on CMML diagnosis, compared with the 2008 WHO criteria, through a retrospective review of the medical records of 38 CMML patients diagnosed according to the 2008 WHO classification. Application of the 2016 WHO criteria resulted in the exclusion of three (8%) patients who did not fulfill the relative monocytosis criterion and eight (21%) patients with an MPN-associated mutation. These 11 patients formed the 2016 WHO others group; the remaining 27 formed the 2016 WHO CMML group. The significant difference in the platelet count and monocyte percentage between the two groups indicated that the 2016 WHO criteria lead to a more homogenous and improved definition of CMML compared with the 2008 WHO criteria, which may have led to over-diagnosis of CMML. More widespread use of molecular tests and more sophisticated clinical and morphological evaluations are necessary to diagnose CMML accurately.
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Humains , Moelle osseuse , Classification , Diagnostic , Leucémie myélomonocytaire chronique , Leucocytes , Dossiers médicaux , Monocytes , Numération des plaquettes , Études rétrospectivesRésumé
BACKGROUND: Mixed gliomas, such as oligoastrocytomas (OA), anaplastic oligoastrocytomas, and glioblastomas (GBMs) with an oligodendroglial component (GBMO) are defined as tumors composed of a mixture of two distinct neoplastic cell types, astrocytic and oligodendroglial. Recently, mutations ATRX and TP53, and codeletion of 1p/19q are shown to be genetic hallmarks of astrocytic and oligodendroglial tumors, respectively. Subsequent molecular analyses of mixed gliomas preferred the reclassification to either oligodendroglioma or astrocytoma. This study was designed to apply genetically integrated diagnostic criteria to mixed gliomas and determine usefulness and prognostic value of new classification in Korean patients. METHODS: Fifty-eight cases of mixed OAs and GBMOs were retrieved from the pathology archives of Seoul National University Hospital from 2004 to 2015. Reclassification was performed according to genetic and immunohistochemical properties. Clinicopathological characteristics of each subgroup were evaluated. Overall survival was assessed and compared between subgroups. RESULTS: We could reclassify all mixed OAs and GBMOs into either astrocytic or oligodendroglial tumors. Notably, 29 GBMOs could be reclassified into 11 cases of GBM, IDH-mutant, 16 cases of GBM, IDH-wildtype, and two cases of anaplastic oligodendroglioma, IDH mutant. Overall survival was significantly different among these new groups (p<.001). Overall survival and progression-free survival were statistically better in gliomas with IDH mutation, ATRX mutation, no microscopic necrosis, and young patient age (cut off, 45 years old). CONCLUSIONS: Our results strongly suggest that a genetically integrated diagnosis of glioma better reflects prognosis than former morphology-based methods.
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Humains , Astrocytome , Classification , Diagnostic , Survie sans rechute , Génétique , Glioblastome , Gliome , Nécrose , Oligodendrogliome , Anatomopathologie , Pronostic , SéoulRésumé
Brain tumour occurrence in Malaysia demonstrates an increasing trend from year to year among adults and the second most common cancer among children. Thus, the expansion of numerous research for novel therapy and treatment are necessary. The distribution of brain tumour in a specific population is important to provide substantial information about the current trends for developing new diagnostic technique and research. Consequently, this study is opted to provide descriptive data of brain tumour in Hospital Universiti Sains Malaysia (USM). 217 brain tumour cases were collected from the hospital record between 2011 and 2014. The brain tumour cases were confirmed by pathologists according to WHO classification and grading. Descriptive analysis was evaluated by using Microsoft Excel and IBM SPSS version 22. Gender preponderance in this study shows very little difference. The most common adult primary brain tumour in this study was meningioma (32.7%) followed by glioblastoma (7.8%), a type of diffuse astrocytic tumour. According to age factor, brain tumour distribution pattern shows an increasing trend as the age increases and meningioma is the most common among the elder patients. Secondary tumour takes more than 10% from overall percentage of brain tumour cases. In conclusion, the descriptive data presentation in this study is very helpful to provide baseline information on the current brain tumour occurrence in this region.
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@#Brain tumour occurrence in Malaysia demonstrates an increasing trend from year to year among adults and the second most common cancer among children. Thus, the expansion of numerous research for novel therapy and treatment are necessary. The distribution of brain tumour in a specific population is important to provide substantial information about the current trends for developing new diagnostic technique and research. Consequently, this study is opted to provide descriptive data of brain tumour in Hospital Universiti Sains Malaysia (USM). 217 brain tumour cases were collected from the hospital record between 2011 and 2014. The brain tumour cases were confirmed by pathologists according to WHO classification and grading. Descriptive analysis was evaluated by using Microsoft Excel and IBM SPSS version 22. Gender preponderance in this study shows very little difference. The most common adult primary brain tumour in this study was meningioma (32.7%) followed by glioblastoma (7.8%), a type of diffuse astrocytic tumour. According to age factor, brain tumour distribution pattern shows an increasing trend as the age increases and meningioma is the most common among the elder patients. Secondary tumour takes more than 10% from overall percentage of brain tumour cases. In conclusion, the descriptive data presentation in this study is very helpful to provide baseline information on the current brain tumour occurrence in this region.
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Tumeurs du cerveauRésumé
BACKGROUND: Different criteria have been used to diagnose mixed-phenotype acute leukemia (MPAL), which has impacted the number of individuals diagnosed with this pathology. Better outcomes have been reported when using acute lymphoblastic leukemia (ALL)-type chemotherapy in the treatment of MPAL. METHODS: We compared the outcome of 4 groups of patients with MPAL. Group 1 included patients diagnosed using the 2008/2016 World Health Organization (WHO) classification; group 2 included patients diagnosed using the European Group for the Immunological Characterization of Leukemias (EGIL) criteria; group 3 included patients diagnosed using either the EGIL or the 2008/2016 WHO criteria; and group 4 was comprised of patients diagnosed with MPAL using the EGIL classification only. RESULTS: We found a significantly worse disease-free survival (groups 1-4) and overall survival (OS) (groups 2 and 3) when comparing MPAL patients to other acute leukemia (AL) patients. A significantly better OS was obtained in patients (groups 2-4) treated with ALL-type chemotherapy compared to acute myeloid leukemia (AML)-type regimens. CONCLUSION: In light of these results, and because a trend (P=0.06) was found with regard to a better OS in group 4 when compared to other AL patients, an argument can be made that the 2008/2016 WHO classification is underpowered to diagnose all MPAL cases, potentially resulting in the suboptimal treatment of some individuals with AL.
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Humains , Classification , Survie sans rechute , Traitement médicamenteux , Leucémies , Leucémie aigüe myéloïde , Anatomopathologie , Leucémie-lymphome lymphoblastique à précurseurs B et T , Organisation mondiale de la santéRésumé
Background: The salivary glands are one of the few tissues in the body that are subjected to diverse and heterogeneous range of tumors and tumor like conditions. The relative infrequency of these tumors makes their diagnosis and management quite complicated. Fine needle aspiration cytology (FNAC) is a useful diagnostic procedure which has a recognized role in the evaluation of salivary gland lesions. A pre-operative diagnosis about nature of lesion, whether benign or malignant, will help in making decision about proper management of patient. Objective: Aim of this study was to know the epidemiology of salivary gland tumors in our region and to evaluate sensitivity, specificity and diagnostic accuracy of fine needle aspiration cytology taking histopathology as the gold standard. Method: It was prospective observational study conducted in department of pathology in our institute. Total 100 cases were studied with particular reference to age, sex, site, cytologic details & histological types as per WHO classification. FNAC & histopathological examination was done in all cases. Correlation between cytological & histopathological diagnoses was assessed. Diagnostic accuracy of FNAC was evaluated by comparing cytological & histopathological diagnoses. Results: Parotid gland was the most common site of involvement (70% cases). Maximum number of patients was in age range of 41-50 years & male to female ratio was 0.8:1. Most common benign & malignant tumors were pleomorphic adenoma (69.89% cases) & mucoepidermoid carcinoma (8.60% cases) respectively. On cytology, 93 cases while on histopathology 96 cases were diagnosed as neoplastic. Cytological diagnoses correlated with histopathological diagnoses in 94% cases. Sensitivity, specificity & diagnostic accuracy of FNAC were found to be 96.87%, 100% & 96% respectively. Conclusion: FNAC in salivary gland masses is fairly reliable for correct preoperative diagnosis. Multiple sampling and special attention to cytologic features should help to minimize errors.
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Objective:To investigate the correlations of Lauren classification and world health organization (WHO) classification of gastric cancer (GC) with microvascular density (MVD), matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), vascular endothelial growth factor (VEGF), vascular endothelial growth factor receptor 1 (VEGFR1), vascular endothelial growth factor receptor 2 (VEGFR2), and p53. Methods:The clinical data of 89 patients with GC were collected. The collected specimens were categorized on the basis of Lauren classification and WHO classification. CD34/periodic acid-Schiff (PAS) double staining was performed to validate MVD. Immunohistochemistry was conducted to investigate the expression levels of MMP-2, MMP-9, VEGF, VEGFR1, VEGFR2, and p53. Results:MVD was not correlated with Lauren classification or WHO classification (P>0.05). Lauren typing was associated with the expression levels of MMP-9, VEGFR1, and p53 (P0.05). Cox proportional hazards model revealed that Lauren classification and WHO classification were the prognostic factors of overall survival (P<0.05). Conclusion:This research on tumor related factors, angiogenesis, and different classifications of GC may provide new methods to treat this disease.
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Dengue disease has a wide clinical spectrum that spans from asymptomatic or mild infection to life-threatening disease. The approach to dengue has recently been revised and dengue can be classified in terms of disease severity. This new approach, which makes use of warning signs, is useful to the primary care physician who is often the first line of contact as it guides triaging, serves as decision support for who can be managed in the outpatient setting, and flags up those who should be sent to hospital for further evaluation and management. This review article aims to familiarise primary care physicians with the use of this new classification, provide background on its development and give an understanding of principles of this new approach.
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Purpose To study the pathologic types and subtypes distribution of 645 cases of lymphoma in Xinjiang. Methods Clini-cal data of lymphoma from April 2008 to march 2013 in the people’s hospital of Xinjiang Uygur autonomous region in Xinjiang were col-lected and reviewed, including morphological, immunohistochemical and clinical characteristics. According to the WHO classification all the cases were reappraised. Results Of the 645 cases, 558 cases (86.51%) were non-Hodgkin’s lymphoma (NHL) and 82 ca-ses (12.71%) were Hodgkin’s lymphoma (HL). Among NHL cases, 448 cases (80.29%) were B-cell neoplasms and 110 cases (19.71%) were T/NK-cell neoplasms. The commonest subtype was diffuse large B-cell lymphoma (258 cases, comprising 40% of all lymphomas) and extranodal NK/T-cell lymphoma (41 cases, comprising 6.36% of all lymphomas) in B cell lymphoma and T/NK cell lymphoma. Burkitt’s lymphoma and lymphoblastic leukemia/lymphoma were predominanly Uyghurs, but mantle cell lymphoma, follicu-lar lymphoma and extranodal marginal zone lymphoma of mucosa associated lymphoid tissue were predominanly Hans. The most com-mon subtypes of Hodgkin’s lymphoma are mixed cellularity, nodular sclerosis and lymphocyte-rich classical Hodgkin’s lymphoma. Sub-types distribution of Hodgkin’s lymphoma has a certain difference in the different ethnic groups, the age of onset did not present twin peaks and the highest proportion was children. Conclusion The lymphoid neoplasms of Xinjiang displayed some ethnic features simi-lar to those reported in literature as well as other regions of China, whereas the distribution of some subtypes showed some differences.
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Objective To study the expression of P63 in 76 patients with thymic epithelial tumors (TET, including thymomas and thymic carcinomas) and its role in pathological diagnosis of TET based on World Health Organization classification. Methods Immunohistochemistry (SP method) was used to detect P63 expression in 76 different subtypes of TET tissues. The initial diagnostic results, further diagnosis results and diagnostic results considering P63 expression were analyzed and compared. Results The further diagnosis results identified 9 cases of misdiagnosis (mainly AB and B subtypes) and 3 uncertain cases. Different degrees of P63 expression (located in the nuclei) was observed in 72 cases, and different subtypes had different expression patterns. The diagnostic results considering P63 expression were more accurate than those not considering P63 expression (TET, P = 0. 017 and thymoma, P = 0. 032, respectively). Detection of P63 expression helped to confirm the diagnosis of the 3 uncertain cases according to the further diagnosis results. Conclusion Considering that P63 expression can help to better differentiate the subtypes of thymoma, it should be used as a routine marker for clinical diagnosis, especially for AB and B subtype thymoma.
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Objective To analyze diagnostic classification and karyotype characteristics of patients with myelodysplastic syndrome(MDS)in Xinjiang Uygur Autonomous Region.Methods 149 patients with MDS were retrospective observed.The features of clinical,laboratory examination,morphologic and cytogenetics were analyzed from patients classified by the 2008 WHO classification.The rates of survival and leukemia conversion in different subgroups,the differences between uygur and han nationalities,and the rates of abnormal karyotypes in different subgroups were compared.Results Among 149 cases,there were 28 cases of RCUD(including 25 RA and 3 RN),8 cases of RARS,32 cases of RCMD,30 cases of RAEB-Ⅰ,44 cases of RAEB-1,5 cases of MDS-U and 2 cases of 5q-.There was no difference between uygur and han nationality of diagnostic classification(x2=3.627,P=0.822).The overall survival time and AML conversion rates were different among subtype groups.Karyotype abnormalities were found in 74 cases(49.7 %),which showed no difference between uygur and han nationalities.The distribution of karyotype were normal karyotype(72 cases),complex karyotype(34 cases),+8(14 cases),-7(11 cases),+11(7 cases),20q-(5cases),-Y(2 cases),+21(2 cases)and 5q-(2 cases),which were no differences between uygur and ban nationality(X2=10.015,P=0.264).When comparing abnormal karyotype rates in different diagnostic classification subgroups excepting 5q-,RAEB-Ⅰ and RAEB-Ⅱ subtype were higher than that of RCUD subtype(X2=7.034,P=0.008;X2=6.395,P=0.016).Conclusions According to the 2008 WHO classification,the incidence of abnormal karyotype,survival time and AML conversion rates are different among subtype groups.There are no regional and ethnical differences in distribution of diagnostic classification and karyotype in patients with MDS in Xinjiang Uygur Autonomous Region.
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BACKGROUND: The purpose of the present study was to investigate the clinico-hematological findings of bone marrow (BM) involvement and leukemic phase in Korean patients with non-Hodgkin lymphoma (NHL). METHODS: We included 791 patients with NHL that were classified with the WHO (2008) criteria. Laboratory data, bone marrow histomorphologic features and medical records were reviewed. Leukemic phase was defined as when the proportion of neoplastic lymphoid cells comprised more than 10% of leukocytes in the peripheral blood or more than 25% of nucleated cells in the BM. RESULTS: We found that 21.7% (172/791) of the patients had BM involvement, and 6.2% (49/791) developed leukemic phase of the disease. NHL subtypes showing high frequencies of leukemic phase development were mantle cell lymphoma (40%), angioimmunoblastic T cell lymphoma (40%), lymphoblastic lymphoma (36.4%), and Burkitt lymphoma (26.1%). Compared to B-cell type, T-cell type of NHL showed significantly higher frequencies of BM involvement (18.6% vs 30.9%; P=0.0004) and leukemic phase development (4.8% vs 10.3%, P=0.008). Complete remission rate was significantly lower in leukemic (55.6%) than in non-leukemic (85.9%) group of patients (P=0.0002), whereas relapse rate was not different between the two groups. Death rate was higher in leukemic (46.9%) than in non-leukemic (30.1%) group of patients, and the 5-yr overall survival probability was significantly lower in leukemic group (P=0.02). CONCLUSIONS: The incidence of leukemic phase development in NHL was lower in Korean patients than that reported for Western populations and higher in T-cell lymphoma. We confirmed that the presence of leukemic phase in NHL patients is associated with a poor prognosis.