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A 31-year-old man presented with left cervical and left inguinal masses and intermittent itching and night sweats for 2 years. What is your diagnosis?
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Eosinofilia , Masculino , Humanos , Eosinofilia/diagnóstico , Eosinofilia/etiología , Diagnóstico DiferencialRESUMEN
OBJECTIVES: The aim of this systematic review is to investigate different diagnostic methods and the available treatment options for subcutaneous panniculitis-like T-cell lymphoma (SPTCL). METHODS: We searched PubMed, Web of Science, SCOPUS, EBSCO, and CINAHL Plus for published case reports of SPTCL. From each record, we extracted data of the diagnostic methods, immunohistochemical profile, clinical characteristics, and the treatment approaches provided. Data were summarized and narratively synthesized to highlight the various diagnostic methods and treatment options of SPTCL. RESULTS: Our literature search yielded 1293 unique citations. Following screening, nine articles reporting a total of 15 cases were included in this systematic review. All patients presented with subcutaneous nodules. Three of the 15 cases were initially misdiagnosed. The atypical lymphoid cells were positive for CD2, CD3, granzyme B, and TIA-1 and negative for CD1a, EBER, and CD20 in all the reported cases. The atypical lymphoid cells were positive for CD45RO in four out of seven cases, positive for CD56 in three out of 12 cases tested, while positive for CD5 and CD8 in the majority of cases. Therapy ranged from topical agents to immunosuppressive agents all the way to multiagent chemotherapy. CONCLUSION: SPTCL is a rare lymphoma. Diagnosis is highly dependent on the immunohistochemical stains added to histopathologic and radiologic findings. Therapy is dependent on the pace of the disease, with encouraging results obtained with single-agent cyclosporine.
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Linfoma Cutáneo de Células T , Linfoma de Células T , Paniculitis , Neoplasias Cutáneas , Humanos , Linfoma Cutáneo de Células T/terapia , Linfoma Cutáneo de Células T/tratamiento farmacológico , Linfoma de Células T/diagnóstico , Linfoma de Células T/terapia , Linfoma de Células T/patología , Paniculitis/diagnóstico , Paniculitis/terapia , Paniculitis/patología , Neoplasias Cutáneas/patologíaRESUMEN
BACKGROUND: Laboratory hematological tests are widely used in clinical practice to assess health and disease conditions. Reference ranges provided by laboratory reports are considered the most authoritative medical tools to assist in the decision-making phase. International standards institutes recommend that reference ranges be established for each region. OBJECTIVES: Provide reference values of routine hematological parameters in Saudi adults according to age and gender. DESIGN: Cross-sectional SETTING: Central province of Saudi Arabia. PATIENTS AND METHODS: Apparently healthy Saudi adults were subjected to laboratory testing of routine hematological parameters (full blood count, hemostatic profile, and serum hematinics), after completing a detailed health medical questionnaire. MAIN OUTCOME MEASURES: Hematological reference values based on the local population. SAMPLE SIZE AND CHARACTERISTICS: 637 after screening 827 potentially healthy Saudi adults with ages ranging from 15 to 65 years. RESULTS: The reference values of routine hematological parameters for the full population and by gender are presented with 90% CI as the lower and upper limits. Reference ranges mostly differed from universal established ranges shown in textbooks. CONCLUSION: The reference ranges of routine hematologic parameters for accurate assessment and appropriate management will help improve the routine clinical care of the adult Saudi population. LIMITATIONS: Difficulty in assessing health status of participants, who could have subclinical illnesses not reflected in the evaluated blood measurement. Lack of ability to eliminate individuals who might be carriers for haemoglobinopathies. Studies with larger sample sizes from different areas of the country are required to achieve a more accurate representation of the whole Saudi population. CONFLICT OF INTEREST: None.
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Pruebas Hematológicas , Adolescente , Adulto , Anciano , Estudios Transversales , Humanos , Persona de Mediana Edad , Valores de Referencia , Arabia Saudita , Adulto JovenRESUMEN
BACKGROUND/OBJECTIVE: Myelodysplastic syndrome (MDS) is a clonal disorder of hematopoietic stem cells, characterized by ineffective hematopoiesis, peripheral cytopenias along with hypercellularity of the bone marrow, and marked dysplastic features. Establishing MDS diagnosis is difficult due to nonspecific clinical presentation and imprecise morphological criteria. In anticipation to improve the diagnostic approach in this field, we aimed to characterize the clinical and morphological features of patients presented with cytopenias with a special focus on MDS. METHODS: We comprehensively reviewed all medical record of patients who were referred to the hematology laboratory at KFSH-RC, Riyadh, Saudi Arabia, between January 2009 and March 2016 for evaluation of bone marrow aspirates and trephine biopsies due to severe and persistent cytopenia(s) to rule out MDS. RESULTS: A total of 183 patients, 155 adult and 28 pediatric, were identified. In the adult group, MDS was diagnosed in 82 (52.9%) patients, with a male-to-female (M:F) ratio of 1.6:1 and mean age at diagnosis of 50 years. According to the World Health Organization (WHO) 2017 criteria, MDS subtypes were as follows: MDS with single lineage dysplasia (SLD, 5%), MDS with ring sideroblasts and SLD (MDS-RS-SLD 7%), MDS with multilineage dysplasia (MDS-MLD 21%), MDS with deletion of chromosome 5q (MDS del(5q), 2%), MDS unclassifiable (MDS-U7%), hypoplastic MDS (h-MDS 4%), MDS with excess blasts-1 (MDS-EB1, 20%), MDS with excess blasts-2 (MDS-EB2, 28%), and therapy-related MDS (6%). Laboratory and morphological features were described. In both groups, cytogenetic abnormalities were classified according to the Revised International Prognostic Scoring System cytogenetic risk groups. In adults, the dominating cytogenetic abnormalities were monosomy 5 and monosomy 7 seen in 20.7% and 24.4% of patients, respectively. Peripheral cytopenia not due to MDS was diagnosed in 54 (34.8%) patients, with a mean age of 43 years and M:F ratio of 1:1. The cause of these cytopenias were as follows: bone marrow failure (BMF, 22%), peripheral destruction (20%), drug induced (20%), anemia of chronic disease (16%), B12 deficiency (7%), infection (7%), paroxysmal nocturnal hemoglobinuria (4%), idiopathic cytopenia of undetermined significance (2%), and idiopathic dysplasia of undetermined significance (2%). A definite diagnosis of MDS was not possible in 19 patients due to insufficient clinical data. In the pediatric group, MDS was diagnosed in 14/28 (50%) patients, with M:F ratio of 1.8:1 and mean age at diagnosis of 4 years. MDS subtypes (WHO 2017) in 14 patients were as follows: refractory cytopenia of childhood (RCC, 42.8%), MDS-EB1 (42.8%), and MDS-EB2 (14.2%). Laboratory and morphological features were described. The prevalent cytogenetic abnormality was monosomy 7 in six/14 (42.8%) patients. Cytopenias due to other causes were diagnosed in eight/28 patients (28.5%), with a mean age of 6.5 years and M:F ratio of 1.6:1. The causes of non-MDS related cytopenia were: congenital BMF (4 patients), peripheral destruction (2 patients), immune deficiency (1 patient), and viral infection (1 patient). A definite diagnosis of MDS could not be made in six/28 (21.4%) patients. CONCLUSION: MDS is the cause of cytopenia in a significant number of patients referred for evaluation of cytopenias, appears at younger age, and tends to be more aggressive than that reported in international studies. Anemia, dysplastic neutrophils in the peripheral blood, and dysplastic megakaryocytes in the bone marrow trephine biopsy are the most reliable features in distinguishing MDS from other alternative diagnoses.
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Anemia , Síndromes Mielodisplásicos , Adulto , Humanos , Masculino , Femenino , Niño , Persona de Mediana Edad , Preescolar , Arabia Saudita/epidemiología , Síndromes Mielodisplásicos/diagnóstico , Síndromes Mielodisplásicos/epidemiología , Síndromes Mielodisplásicos/genética , Aberraciones CromosómicasRESUMEN
Rosai-Dorfman-Destombes disease (RDD) is a rare histocytic disorder with a broad spectrum of clinical presentations. The disease typically presents with lymphadenopathy but may involve multiple systems. Usually, RDD lesions demonstrate intense 18F-Fluorodeoxyglucose (FDG) uptake in positron emission tomography/computed tomography (PET/CT) imaging due to the inflammation and infiltration with high metabolic process of the disease. Here, we describe a rare case of 37-year-old man who presented with multiple systemic symptoms, including fever, weight loss and bilateral cervical, and inguinal lymphadenopathy who underwent FDG PET/CT for detection of disease extension. This case highlights the role of FDG PET/CT in establishing the disease extent in newly diagnosed RDD and guiding the therapeutic recommendations and for follow-up to monitor the disease response to therapy. To the best of our knowledge, this is the first case report from Saudi Arabia highlighting the role of FDG PET/CT in newly diagnosed RDD.
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BACKGROUND: Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is an uncommon variant of Hodgkin lymphoma. There is limited data on treatment, management of refractory and relapsed disease, and long-term outcome. Many registries or country-wide data reports are unable to provide detailed primary and subsequent management. We are reporting our observation on patient's characteristics, management, and outcome. METHODS: This single-institution retrospective cohort analysis includes NLPHL patients seen from 1998 to July 2019. We used Fisher's exact test, chi-square, and Kaplan-Meier (KM) method for various analyses. RESULTS: Two hundred patients were identified, (6.34% of all the HL). Male:female was 3:1. The median age at diagnosis was 22 years (4-79 years). Stage I-II in 145 (72.5%) cases. One hundred patients (50%) received chemotherapy, 68 (34%) chemotherapy + radiation therapy (RT); 87% of all chemotherapy was ABVD (adriamycin, bleomycin, vinblastine, dacarbazine). Thirteen patients (6.5%) received RT alone and 16 (8%) had surgery alone. Complete response in 82%, partial response in 5.5% and progressive disease in 10.5%. The median follow is 60 months (5-246). Median 5 and 10 years overall survival (OS) is 94.8 and 92.4% (stages I-II, 97.7 and 97.7%, stage III-IV, 94.8 and 92.4%). Median event-free survival (EFS) is 62.3 and 54% respectively (stage I-II, 72 and 64%, stage III-IV, 36.4 and 18.2%). Stage I-II vs III-IV OS (p = < 0.001) and EFS (p = < 0.001) were significant. For stage I-II, 5 year EFS of chemotherapy + RT (83.3%) was superior to chemotherapy alone (60%, p = 0.008). Five year EFS for early favorable (80%), early unfavorable (60%), and advanced (36.4%) was significant (p = < 0.001). Eleven patients (5.5%) had high-grade transformation. Twenty-nine patients underwent HDC auto-SCT, all are alive (28 in remission). 25% of patients had pathologically proved nodal hyperplasia at some point in time. CONCLUSION: OS of NLPHL is excellent and independent of treatment type. EFS is better for chemotherapy + RT than chemotherapy alone. Stem cell transplant in refractory / multiple relapses resulted in excellent disease control. There is a need to identify optimal treatment strategies accordingly to the risk stratification.
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Enfermedad de Hodgkin/terapia , Adolescente , Adulto , Anciano , Niño , Preescolar , Femenino , Enfermedad de Hodgkin/patología , Humanos , Masculino , Persona de Mediana Edad , Medio Oriente , Recurrencia Local de Neoplasia , Resultado del Tratamiento , Adulto JovenRESUMEN
Tubulocystic renal cell carcinoma (RCC) is one of the newly recognized subtypes of RCC. It has a unique cystic morphology and indolent behavior. During the last decade, few studies have been published describing tubulocystic RCC with poorly differentiated foci. A subset of these cases are associated with loss of fumarate hydratase which is a characteristic feature of hereditary leiomyomatosis and renal cell carcinoma-associated RCC. However, these two entities represent two distinct subtypes of RCC in the recent WHO Classification of kidney tumors. Herein, we are describing a rare case of tubulocystic renal cell carcinoma with poorly differentiated foci and loss of fumarate hydratase.
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Rapidly progressive interstitial lung disease is typically associated with clinically amyopathic dermatomyositis and the anti-melanoma differentiation associated gene 5 antibody, a condition with high mortality and resistance to classic immunosuppression. Recent reports have described the efficacy of the Janus kinase inhibitor tofacitinib in the treatment of rapidly progressive interstitial lung disease in anti-melanoma differentiation associated gene 5 antibody-positive clinically amyopathic dermatomyositis. It is uncertain, however, whether tofacitinib alters the course of rapidly progressive interstitial lung disease in other variants of dermatomyositis that are unrelated to the anti-melanoma differentiation associated gene 5 antibody and whether the early addition of the anti-fibrotic tyrosine kinase inhibitor nintedanib interferes with the development of fibrosis. To answer these questions, we present and discuss the case of an elderly woman who presented with a flare of dermatomyositis sine myositis. Based upon the detection of anti-Jo-1 antibodies and the absence of anti-melanoma differentiation associated gene 5 antibodies, anti-synthetase syndrome was diagnosed. While the cutaneous manifestations quickly resolved with prednisone, azathioprine and tacrolimus, the respiratory function paradoxically and rapidly deteriorated, and invoked the use of tofacitinib. Markedly raised ferritin levels and a severe numerical deficiency of circulating natural killer cells paralleled the acute lung inflammation, which was reflected by 18F-fluorodeoxyglucose hypermetabolism on positron emission tomography/CT. Tofacitinib lead to a prompt clinical recovery, with a reduction in oxygen requirement, correction of hyperferritinemia, reversal of the natural killer cell deficiency, and a decrease in 18F-fluorodeoxyglucose uptake in the affected lung segments. Subsequently, nintedanib was added at a point in time when inflammation subsided. Apart from cytomegalovirus reactivation no adverse events occurred. In conclusion, tofacitinib reversed the pronounced inflammatory component of anti-Jo-1 antibody-positive, anti-melanoma differentiation associated gene 5 antibody-negative rapidly progressive interstitial lung disease, confirming that Janus kinase signaling pathways are critically involved in the pathogenesis of rapidly progressive interstitial lung disease, apparently independently of the targeted autoantigen. Although some improvement in pulmonary function was observed, it seems premature to conclusively judge on reversibility or prevention of pulmonary fibrosis by pairing both kinase inhibitors for which an extended follow-up and ideally, prospective and controlled studies are needed.
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Teratoid Wilms tumor is a rare variant of Wilms tumor composed predominantly of well-differentiated epithelial and/or mesenchymal heterologous elements. Like the classical Wilms tumor, this variant may also occur as a renal mass or may be found in extra renal locations. This tumor may be treated effectively by surgical resection; however, it generally fails to respond to chemotherapy. A review of the literature revealed 30 reported cases of intra renal and 5 reports of extra renal teratoid Wilms tumor. We report our experience with an additional three cases of renal teratoid Wilms tumor adding to the 30 cases previously reported.
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Neoplasias Renales/patología , Teratoma/patología , Tumor de Wilms/patología , Niño , Preescolar , ADN de Neoplasias/química , Exones/genética , Femenino , Humanos , Lactante , Neoplasias Renales/genética , Neoplasias Renales/cirugía , Masculino , Nefrectomía , Teratoma/genética , Teratoma/cirugía , Tumor de Wilms/genética , Tumor de Wilms/cirugíaRESUMEN
INTRODUCTION: Persistent Müllerian Duct Syndrome (PMDS) is a rare sexual disease. It is characterized by the presence of female reproductive structures such as uterus, cervix, fallopian tubes and upper part of vagina in a normal genotypically and phenotypically male. The diagnosis is usually incidental since the patients will present with normal external genitalia and secondary sexual characteristics. Imaging techniques such as magnetic resonance imaging (MRI), computed tomography (CT) scan, or ultrasound (US) could help in the diagnosis. CASE PRESENTATION: A 45-year-old male presented with bilateral undescended testes since birth and 2 months history abdominal mass. CT scan showed a 13â¯×â¯17â¯×â¯20â¯cm solid pelvi-abdominal mass. The diagnosis of mixed germ cell tumor of the undescended testes was made based on the CT scan. During resection of the tumor, patient was found to have a uterus, fallopian tubes and ovaries. DISCUSSION: Pathological investigation showed endometrial tissues with portion of lower uterine segment and cervix with remnant of testes with marked atrophy. No Ovarian tissues were found nor fallopian tube as well. The diagnosis of PMDS was made based on the pathological report. CONCLUSION: PMDS is a challenging condition to diagnose. Radiological investigation can miss the presence of the Müllerian duct structures as in our case because of the unusual presentation of this condition. Early diagnosis and management is important as the malignant transformation is high due to the undescended testes.
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Patients with isolated methylmalonic acidemia (MMA) may present with a wide range of hematological complications including anemia, leukopenia, thrombocytopenia, and pancytopenia. However, there are very limited data on the development of hemophagocytosis or myelodysplasia in these patients. We report three patients with isolated MUT related MMA who presented with severe refractory pancytopenia during acute illness. Their bone marrow examination revealed a wide spectrum of pathology varying from bone marrow hypoplasia, hemophagocytosis to myelodysplasia with ring sideroblasts. We discuss their management and outcome. This report emphasizes the need for bone marrow examination in these patients with refractory or unexplained severe cytopenia, to confirm bone marrow pathology, and to rule out other diseases with similar clinical presentation for a better clinical outcome.
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Errores Innatos del Metabolismo de los Aminoácidos/sangre , Errores Innatos del Metabolismo de los Aminoácidos/diagnóstico , Médula Ósea/patología , Pancitopenia/sangre , Adolescente , Alelos , Errores Innatos del Metabolismo de los Aminoácidos/genética , Biomarcadores , Examen de la Médula Ósea , Femenino , Genotipo , Humanos , Masculino , Metilmalonil-CoA Mutasa/genética , Mutación , FenotipoRESUMEN
We report an unusual case of recurrent encephalopathy due to acquired hemophagocytic lymphohistiocytosis (HLH) in a patient with propionic acidemia (PA). PA is an inherited metabolic disorder in which patients often present with encephalopathy and pancytopenia during metabolic decompensation. However, these patients may rarely develop HLH with similar presentation. This case illustrates the need to distinguish HLH induced encephalopathy from the one secondary to metabolic decompensation in these patients, as early diagnosis and treatment of HLH improves prognosis. This case also highlights the importance of considering HLH in patients presenting with unexplained encephalopathy, as early diagnosis and treatment is lifesaving in this otherwise lethal condition. To our knowledge this is the first case report of acquired HLH presenting as recurrent encephalopathy followed by complete recovery, in a metabolically stable patient with PA.
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Cancer is a common and potentially deadly disease. Some of the cancers may be difficult to treat by conventional means such as surgery, radiation, and chemotherapy, but may be controlled by the stimulation of the immune response of the body with the help of cancer vaccines. The use of vaccines for preventing infections by oncogenic viruses such as hepatitis B virus and human papilloma virus has been extremely successful in reducing the incidence of cancers resulting from these infections. The use of vaccines for treating cancers that are not due to viral infections and that are already established is currently the object of numerous clinical trials. Several types of cancer vaccines are being tried. These include antigen vaccines, tumor cell vaccines, dendritic vaccines, deoxyribonucleic acid vaccines, and viral vector vaccines. The development of these therapeutic vaccines is proving difficult with only 1 recent success. However, there is significant enthusiasm and optimism regarding the development of effective therapeutic vaccines stemming from the fact that our understanding regarding the cancer immunology is considerably enhanced in recent years. This expanded knowledge regarding the mechanisms that cancers use to escape the immune system is likely to open new avenues in modulating the immune response to cancer, thus enhancing the effectiveness of therapeutic cancer vaccines.
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Vacunas contra el Cáncer , HumanosRESUMEN
Germ cell tumors of the testis may be divided into 3 broad categories according to age at presentation. The tumors in the pediatric age group include teratoma and yolk sac tumor. These tumors are generally not associated with convincing intratubular neoplasia. The second group consists of tumors presenting in third and fourth decade of life and include seminoma, embryonal carcinoma, yolk sac tumor, choriocarcinoma, and teratoma as well as mixed germ cell tumors. The precursor cell for these tumors is an abnormal gonocyte that fails to differentiate completely into spermatogonia. These abnormal cells stay dormant in the gonad during intrauterine life as well as infancy and childhood, but undergo proliferation during puberty and can be identified as intratubular germ cell neoplasia unclassified (IGCNU). These tumor cells continue to manifest protein expression pattern that resembles primitive germ cells (PLAP, c-KIT, OCT3/4). After a variable interval following puberty, IGCNU cells may acquire ability to penetrate the seminiferous tubules and present as an overt germ cell tumor. Acquisition of isochrome 12 and other genetic abnormalities are usually associated with this transition. The level of DNA methylation generally determines the phenotype of the germ cell tumor. The third type of germ cell tumors is spermatocytic seminoma, which is a rare tumor encountered later in life usually in fifth and sixth decade. The cell of origin of this tumor is probably postpubertal mature spermatogonia which acquire abnormal proliferative capability probably due to gain of chromosome 9 resulting in activation and amplification of genes such as DMRT1. The tumor cells manifest many of the proteins normally expressed by mature sperms such as VASA, SSX2, and occasionally OCT2. Although spermatocytic seminoma may also have an intratubular growth phase, it completely lacks features of IGCNU.
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Neoplasias de Células Germinales y Embrionarias/etiología , Neoplasias Testiculares/etiología , Humanos , Masculino , Neoplasias de Células Germinales y Embrionarias/patología , Factores de Riesgo , Túbulos Seminíferos/patología , Neoplasias Testiculares/patologíaAsunto(s)
Trasplante de Riñón/efectos adversos , Leucemia Promielocítica Aguda/etiología , Donantes de Tejidos , Humanos , Leucemia Promielocítica Aguda/diagnóstico , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias/diagnóstico , Complicaciones Posoperatorias/etiología , Trasplante HomólogoAsunto(s)
Neoplasias del Sistema Nervioso Central/patología , Linfoma de Células B Grandes Difuso/patología , Siembra Neoplásica , Neoplasias del Sistema Nervioso Central/diagnóstico , Neoplasias del Sistema Nervioso Central/terapia , Humanos , Linfoma de Células B Grandes Difuso/diagnóstico , Linfoma de Células B Grandes Difuso/terapia , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Recurrencia Local de Neoplasia , Tomografía Computarizada por Rayos XRESUMEN
BACKGROUND AND OBJECTIVES: The Gleason grading of prostate carcinoma (PCa) in needle core biopsies is a major determinant used in management planning. The objective of this study was to evaluate the concordance between general pathologists Gleason grading and that of a urologic pathologist in our community. DESIGN AND SETTING: Retrospective review conducted at three tertiary care hospitals in Jeddah and Riyadh for all prostatic biopsies with carcinoma from January 2002 to January 2011. METHODS: Gleason scores assigned by the original pathologist were compared with that of the reviewing urologic pathologists. Biopsies were originally obtained and diagnosed at different referring hospitals and independent laboratories. The kappa test was used to evaluate agreement between the original and review scores. RESULTS: For 212 biopsies the exact concordance of the Gleason score assigned by the original pathologist and the reviewer was 38.7% (82/212). However, when grouped into the main four-score categories of 2-4, 5-6, 7, and 8 or greater, disagreement was noted in 88 (41.5%) biopsies; 87 were upgraded and 1 was downgraded on review. When grouped into two-score categories of low grade (≤6) and high grade (≥7), disagreement was noted in 32 (15%) of the biopsies. CONCLUSION: Gleason grade score shows that there was only slight to fair agreement between outside and review scoring (kappa=0.43). When using only low versus high grade categorization, there was good agreement (kappa=0.69). Almost all of the cases with score disagreement were upgraded on review.
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Carcinoma/patología , Clasificación del Tumor/estadística & datos numéricos , Variaciones Dependientes del Observador , Próstata/patología , Neoplasias de la Próstata/patología , Biopsia con Aguja , Humanos , Masculino , Patología , Estudios Retrospectivos , UrologíaAsunto(s)
Médula Ósea/patología , Hiperoxaluria Primaria/complicaciones , Pancitopenia/etiología , Pancitopenia/patología , Adulto , Médula Ósea/metabolismo , Cristalización , Femenino , Humanos , Hiperoxaluria Primaria/metabolismo , Oxalatos/química , Oxalatos/metabolismo , Pancitopenia/metabolismoRESUMEN
The World Health Organization (WHO) classification of lymphomas updated in 2008 represents an international consensus for diagnosis of lymphoid neoplasms based on the recognition of distinct disease entities by applying a constellation of clinical and laboratory features. The 2008 classification has refined and clarified the definitions of well-recognized diseases, identified new entities and variants, and incorporated emerging concepts in the understanding of lymphoid neoplasms. Rather than being a theoretical scheme this classification has used data from published literature. Recent knowledge of molecular pathways has led to identification and development of new diagnostic tools, like gene expression profiling, which could complement existing technologies. However, some questions remain unresolved, such as the extent to which specific genetic or molecular alterations define certain tumors. In general, practical considerations and economics preclude a heavily molecular and genetic approach. The significance of early or precursor lesions and the identification of certain lymphoid neoplasms is less clear at present, but understanding is evolving. The borderline categories having overlapping features with large B-cell lymphomas, as well as some of the provisional entities, are subject to debate and lack consensus in management. Lastly, the sheer number of entities may be overwhelming, especially, for the diagnosing pathologist, who do not see enough of these on a regular basis.