Correlation NKX2.2 IHC and EWSR1 break-apart FISH in the diagnosis of Ewing sarcoma: Can combined NKX2.2 and CD99 immunoexpression obviate or minimize the need of FISH testing? First assessment study from Indian tertiary cancer care center

Context: Ewing sarcoma (ES) are malignant small round cell tumors (MSRCT) characterized by rearrangements of EWSR1 gene. Although gold standard for diagnosis is detection of specific fusion genes by molecular testing, these ancillary tests are costly and only available in limited number of settings. There is a persuasive evidence for reliability of NKX2.2 immunohistochemistry (IHC) as a surrogate marker for EWSR1 gene rearrangement in ES. Aims: The aim of this study is to correlate the NKX2.2 immuno-expression with genetically confirmed ES cases and also to assess the reliability and accuracy of NKX2.2 along with combined positivity of NXX2.2 and CD99 in diagnosing ES and differentiating it from other relevant histological mimics. Settings and Design: The present study is a retrospective study conducted over a period of 6-year duration in a tertiary cancer care center. Methods and Material: We evaluated NKX2.2 immunoexpression in 35 genetically confirmed cases of ES and also in pertaining differential entities (n = 58) of ES including rhabdomyosarcoma (n = 20), lymphoblastic lymphoma (n = 14), Wilms tumor (n = 10), poorly differentiated synovial sarcoma (n = 4), small-cell osteosarcoma (n = 4), neuroblastoma (n = 5), and mesenchymal chondrosarcoma (n = 1). CD99 was performed in the category of MSRCTs showing NKX2.2 positivity to evaluate combined specificity for the diagnosis of ES. Results: Of the 35 genetically confirmed cases of ES, 29 cases (83%) showed NKX2.2-positive expression (83% sensitivity). Compared to ES, NKX2.2 was positive in only 05% cases (3/58 cases) of non-ES MSRCT. Only two of five cases of neuroblastomas and one case of mesenchymal chondrosarcoma showed NKX2.2 positivity. CD99 positivity was seen in 100% of ES and in the single case of mesenchymal chondrosarcoma. All five cases (100%) of neuroblastoma were negative for CD99. Conclusions: The presented study, which is the first from an Indian oncology center, showed NKX2.2 IHC is quite reliable in diagnosis of ES in the right clinicopathological context. With remarkable sensitivity and specificity of NKX2.2 IHC for diagnosis of ES, we propose that combined positivity of CD99 and NKX2.2 IHC can obviate or minimize the need of EWSR1 gene rearrangement molecular testing for diagnosis of ES.

The functional roles and targeted-therapy strategies of CD99 in Ewing sarcoma / 中国肿瘤生物治疗杂志

@#[摘 要] CD99是一种主要定位在细胞膜上的Ⅰ型跨膜糖蛋白，参与调控正常组织细胞的分化、黏附、迁移和蛋白运输等功能。CD99蛋白在大多数正常组织中表达较低，但在一些恶性肿瘤，尤其是尤因肉瘤（EWS）中高表达，可作为EWS的辅助诊断和预后标志物。高表达的CD99蛋白可通过多种机制促进EWS的发生发展，例如与配体结合、影响外泌体相关的miRNA分泌和调控下游信号通路等。作为在EWS细胞中高特异性表达并发挥促癌作用的膜蛋白，CD99是理想的肿瘤治疗靶点，已有研究尝试开发通过靶向CD99治疗EWS的方法，包括CD99中和抗体、小分子抑制剂和肿瘤疫苗等。尽管目前靶向CD99治疗EWS还处于临床前研究阶段，但已展现出很好的治疗前景。因此，针对CD99的靶点干预可能为EWS治疗提供新策略。

Sarcoma de Ewing extraesquelético en cavidad nasal y senos paranasales, reporte de caso / Extra-skeletal Ewing sarcoma in the nasal cavity and paranasal sinus, case report

El sarcoma de ewing es un tumor maligno de rápido crecimiento, con prevalencia de 1-5 casos por cada 1.000.000 habitantes, su forma extraesquelética en la cavidad sinonasal o senos paranasales es inusual. Objetivo: describir la localización atípica de esta neoplasia y la importancia de lograr un diagnóstico oportuno. Paciente femenina, con una masa en la cavidad nasal derecha de dos meses de evolución, cefalea y epistaxis. Con asimetría en región orbitaria derecha y deformidad del tabique nasal, senos paranasales con sintomas de obstrucción. La tomografía reveló una masa que invade senos paranasales. La biopsia mostró un sarcoma de Ewing. Se confirmó con CD99. La paciente recibió quimioterapia y plan de resección quirúrgica, pero falleció. El diagnóstico y tratamiento oportuno del sarcoma de ewing en cavidad sinonasal debe apoyarse con examenes tomográficos, histopatológicos, inmunohistoquímicos y de ser posible citogenéticos para llegar al diagnóstico definitivo en etapas tempranas del tumor

Ewing's sarcoma is a rapidly growing malignant tumor, with a prevalence of 1-5 cases per 1,000,000 inhabitants, its extraskeletal shape in the sinonasal cavity or paranasal sinuses is unusual. Objective: to describe the atypical location of this neoplasm and the importance of achieving a timely diagnosis. Female patient, with a mass in the right nasal cavity of two months of evolution, headache and epistaxis. With asymmetry in the right orbital region and deformity of the nasal septum, paranasal sinuses with symptoms of obstruction. Tomography revealed a mass that invades the paranasal sinuses. The biopsy showed Ewing's sarcoma. It was confirmed with CD99. The patient received chemotherapy and a surgical resection plan, however she died. The timely diagnosis and treatment of Ewing's sarcoma in the sinonasal cavity should not be based solely on clinical evaluation, it requires a tomographic, histopathological, immunohistochemical and, if possible, cytogenetic examination to reach a definitive diagnosis in the early stages of the tumor.

CD99L2 gene and related diseases / 国际儿科学杂志

CD99L2(CD99 antigen-like 2)gene is located at Xq28, which encodes a highly conserved and widely expressed glycosylated transmembrane protein.Since it was first reported in 2003, CD99L2 protein has been regarded as an important adhesion molecule, which plays an important role in inflammation, leukocyte exudation, and lymphoma.However, in recent years, more and more studies have found that this gene is closely related to neurological diseases such as autism spectrum disorder, cerebral palsy, and epilepsy, but the specific mechanism is still unclear, and the function of this gene is still unclear.This article reviews the research progress of CD99L2 gene.

Proteomic analysis and verification of protein expression after upregulation of human CD99 in Hodgkin lymphoma cell line L428 / 中华血液学杂志

Objective: To investigate the proteins expression difference after upregulation of human CD99 in Hodgkin Lymphoma cell line, L428 cell, and verify the function of differential proteins. Methods: The differential proteins were detected by two-dimensional fluorescence difference gel electrophoresis and mass spectrometry analysis, cluster analysis was done by GOfact. Results: There were 38 proteins screened out, of which 21 proteins were positively associated with CD99, while 17 proteins were negative. Among the 38 proteins, 32 proteins participated in biological process, and 35 proteins were involved in the composition and construction. And 28 proteins participated in multifaceted biological activities including antioxidation, protein binding, catalytic activity, regulation of enzyme, signal transduction, molecular structure, regulation of translation and ion transport. Conclusions: The changes of the differential proteins, correlated with cytoskeleton, cell differentiation, signal pathway and regulating gene expression, are closely relevant to the translation between Hodgkin/Reed-Sternberg and B lymphocyte cell.

Proteomic analysis and verification of protein expression after upregulation of human CD99 in Hodgkin lymphoma cell line L428 / 中华血液学杂志

Objective@#To investigate the proteins expression difference after upregulation of human CD99 in Hodgkin Lymphoma cell line, L428 cell, and verify the function of differential proteins.@*Methods@#The differential proteins were detected by two-dimensional fluorescence difference gel electrophoresis and mass spectrometry analysis, cluster analysis was done by GOfact.@*Results@#There were 38 proteins screened out, of which 21 proteins were positively associated with CD99, while 17 proteins were negative. Among the 38 proteins, 32 proteins participated in biological process, and 35 proteins were involved in the composition and construction. And 28 proteins participated in multifaceted biological activities including antioxidation, protein binding, catalytic activity, regulation of enzyme, signal transduction, molecular structure, regulation of translation and ion transport.@*Conclusions@#The changes of the differential proteins, correlated with cytoskeleton, cell differentiation, signal pathway and regulating gene expression, are closely relevant to the translation between Hodgkin/Reed-Sternberg and B lymphocyte cell.

Inhibitory Effects of CD99-derived Peptide CD99CRIII3 on the Extravasation of Monocytes and Inflammatory Reactions in Contact Dermatitis Mouse Model / 체질인류학회지

Leucocyte extravasation has been known to play an important role in inflammatory reactions including contact dermatitis. Previous studies suggested that CD99 regulates β1 integrin activity and may be a novel therapeutic target molecule for inflammatory diseases. In this study, the effects of CD99-derived peptide, CD99CRIII3, on inflammatory reactions in contact dermatitis mouse model were investigated. CD99CRIII3 decreased β1-integrin activity in human monocytic U937 cells. CD99CRIII3 inhibited the adhesion of U937 monocytes to human umbilical vein endothelial cells and their extravasation through human umbilical vein endothelial cells. CD99CRIII3 reduced inflammation in the phorbol myristate acetate-induced contact dermatitis mice in a dose-dependent manner. These results indicate that CD99CRIII3 suppresses the extravasation of monocytes and inflammatory reactions in the animal model of the contact dermatitis, suggesting that CD99CRIII3 could be a new drug candidate against inflammatory skin diseases.

Primary Intracranial Ewing's Sarcoma (Peripheral Primitive Neuroectodermal Tumour of Parietal Bone) with Spinal and Pelvic Metastasis in a Young Female Child: Rare Case Report and Review

Introduction The Peripheral Primitive Neuroectodermal Tumour (pPNET)/Ewing's sarcoma family tumor (ESFT) group is a recently redefined term which includes all small round cell tumors of bone, soft tissue, and nerve with a common neuroectodermal origin. These highly aggressive pediatric soft tissue tumors occur less frequently in the craniospinal axis. Primary cranial lesion associated with spinal and pelvic metastasis is a rare presentation. Clinical Presentation A 9-year old girl was hospitalized with features of progressive increase in intracranial pressure with quadriparesis. The patient had ⅘ quadriparesis with bilateral papilledema. Brain MRI showed a large, hetero intense, contrast enhancing right parietal bony lesion infiltrating the dura with mass effect over the brain. Brain CT showed bony expansion and multiple calvarial lytic lesions. MRI cervical spine revealed collapsed fourth cervical vertebral body with extensive paravertebral and paraspinal soft tissue components with cord compression. Metastatic workup revealed a lytic lesion in the left iliac bone and left lung. The patient underwent a surgically challenging C4 corpectomy with cage fixation followed by craniotomy and excision of parietal bony lesion with titanium mesh cranioplasty in the same sitting. Histopathology revealed pPNET and was confirmed by CD99 positivity. Conclusion This rare multiple site tumor presentation was carefully planned and effectively managed by a combined single-stage surgical approach involving total excision of primary parietal bone and metastatic cervical spine tumors with primary titanium mesh cranioplasty and cervical spine stabilization, followed with radiotherapy and chemotherapy, which resulted in good recovery and improved the overall prognosis for the patient.

Introdução O grupo 'tumor neuroectodérmico primitivo periférico (pPNET) / tumor da família dos sarcomas de Ewing (ESFT)' é um termo recentemente redefinido o qual inclui todos as pequenas arredondadas células de tumor ósseo, tecidos moles e nervos com origem neuroectodérmica comum. Estes tumores pediátricos de tecido mole altamente agressivos ocorrem com menor frequência no eixo cranioespinal. Lesões primárias do crânio associadas a metástase espinhal e pélvica são raras. Relato de Caso Criança de 9 anos de idade hospitalizada com fraturas e pressão intracraniana crescente com quadriparesia. A paciente teve ⅘ de quadriparesia com papiledema bilateral. RM do cérebro por contraste mostrou uma lesão óssea parietal direita extensa e hétero-intensa infiltrando a dura-máter com efeito maciço sobre o cérebro. TC do cérebro mostrou expansão óssea e múltiplas lesões líticas na calota craniana. RM da espinha cervical revelou colapso da quarta vertebra cervical com componentes paravertebral e paraespinal de tecido mole com compressão da medula. Workup metastático revelou uma lesão lítica no ilíaco esquerdo e pulmão esquerdo. A paciente foi submetida a difícil corpectomia da C4 com fixação de cage seguida de craniotomia e excisão da lesão parietal óssea com cranioplastia com malha de titânio na mesma posição. Histopatologia revelou pPNET, confirmada por positividade de CD99. Conclusão Este raro caso com apresentação de múltiplos tumores foi cuidadosamente planejado e eficazmente conduzido por acessos cirúrgicos combinados em fase única envolvendo excisão total do osso parietal primário e tumores metastáticos da espinhal cervical com cranioplastia com malha de titânio e estabilização da espinha cervical, seguida de radioterapia e quimioterapia, resultando em boa recuperação e melhora no prognóstico geral da paciente.

CD99 Is Strongly Expressed in Basal Cells of the Normal Adult Epidermis and Some Subpopulations of Appendages: Comparison with Developing Fetal Skin

BACKGROUND: CD99 is a cell surface transmembrane glycoprotein expressed in various tissues. CD99 is differentially expressed between subpopulations of each tissue and is highly expressed in certain hematopoietic and precursor cells. However, there has been no comprehensive study of CD99 expression in normal skin. We evaluated CD99 expression in normal human skin and developing fetal skin. METHODS: Seventy-five adult skin samples containing normal skin and eight fetal skin samples of different gestational ages were collected. CD99 immunohistochemical staining was performed to evaluate expression pattern in adult and fetal skin samples. CD99 and CD34 expression were compared by double immunofluorescence. RESULTS: In normal adult skin, CD99 was strongly expressed in the membrane of epidermal basal keratinocytes, hair follicle bulges and outer root sheaths, and inner secretory cells of eccrine sweat glands. In fetal skin, CD99 was not expressed on the periderm at 16 weeks of gestation but was expressed in basal cells of fetal skin at around 19 weeks of gestation. CD99 expression became comparable to that of the adult skin after 20 weeks of gestation. CD99 and CD34 were co-expressed in hair follicle outer root sheaths, as seen by double immunofluorescence study. CONCLUSIONS: This is the first study examining CD99 expression pattern in normal adult and fetal skin. CD99 tends to be expressed in the basal/precursor cells of epidermis and in hair follicles. These results provide a basis for future investigation on functions of CD99 in the skin and provide a novel potential target for the treatment of dermatologic lesions.

Solid-pseudopapillary neoplasm of the pancreas: A classical presentation with unique paranuclear dot like immunostaining with CD 99.

A 32-year-old lady presented with a history of abdominal pain and upper abdominal discomfort of 3 months duration. Her imaging studies done at a local hospital showed a solid-cystic mass involving head of the pancreas. The patient was referred to our surgical oncology department. On examination, there was a nontender mass in the epigastrium. An ultrasound scan guided fi ne-needle aspiration (FNA) was done which was showing classical features of solid-pseudo papillary neoplasm of the pancreas. With this preoperative diagnosis patient was taken up for surgery. Per operatively, there was a solid-cystic mass in the head of the pancreas. Pancreaticoduodenectomy was done. Histopathology and immunohistochemistry (IHC) confi rmed the diagnosis of solid-pseudo papillary neoplasm of the pancreas. Apart from the routine IHC panel, CD 99 immunostain was also done which demonstrated the characteristic paranuclear dot-like staining observed in previous studies in the literature.

Sinonasal haemangiopericytoma: histomorphology and differential diagnoses

A 39-year-old female presented with a fleshy nasal polyp occluding the left nasal cavity, associated with haemopurulent discharge. Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) scans of the paranasal cavities revealed a large polypoid tumour arising from the left middle turbinate and obstructing the left maxillary sinus ostium. However, no bony or intracranial involvement was identified. A biopsy revealed a tumour with small blue round cell morphology. The tumour cells showed diffuse strong membranous CD99 positivity and patchy CD34 positivity. Ancillary cytogenetic tests for the EWSR1 and SS18/SYT gene translocations were negative. In view of the non-invasive nature of the tumour and the low cell proliferative index (Ki-67) of 5%, a medial maxillectomy resection was performed. The resection revealed additional areas with spindle-cell morphology and focal haemangiopericytic vasculature. The tumour continued to show immunoreactivity to CD99 and CD34, as well as Smooth Muscle Actin (SMA) and Muscle Specific Actin (MSA). The overall findings are in keeping with a sinonasal haemangiopericytoma. With clear surgical resection margins, the patient is on routine follow-up and is currently disease-free.

Engagement of CD99 Reduces AP-1 Activity by Inducing BATF in the Human Multiple Myeloma Cell Line RPMI8226

CD99 signaling is crucial to a diverse range of biological functions including survival and proliferation. CD99 engagement is reported to augment activator protein-1 (AP-1) activity through mitogen-activated protein (MAP) kinase pathways in a T-lymphoblastic lymphoma cell line Jurkat and in breast cancer cell lines. In this study, we report that CD99 differentially regulated AP-1 activity in the human myeloma cell line RPMI8226. CD99 was highly expressed and the CD99 engagement led to activation of the MAP kinases, but suppressed AP-1 activity by inducing the expression of basic leucine zipper transcription factor, ATF-like (BATF), a negative regulator of AP-1 in RPMI8226 cells. By contrast, engagement of CD99 enhanced AP-1 activity and did not change the BATF expression in Jurkat cells. CD99 engagement reduced the proliferation of RPMI8226 cells and expression of cyclin 1 and 3. Overall, these results suggest novel CD99 functions in RPMI8226 cells.

Urinary Bladder: Primitive Neuroectodermal Tumour/Ewing's Tumour – A Rare Case

We hereby report a rare case of primary primitive neuroectodermal tumour (PNET)/Ewing's tumour of the urinary bladder. Primary PNETs of the bladder are very aggressive neoplasms. They are extremely rare and only 12, as on July 2014, have been reported in the literature. A young 22-year old male patient, agricultural labourer by occupation, presented with complaints of urinary obstruction and haematuria of 1-month duration. A provisional diagnosis of small round cell tumour was considered on examination of the biopsy specimen. Subsequently, the panel of immunohistochemical markers CD-99, NSE, LCA, Desmin and vimentin were performed and finally reported as urinary bladder – PNET/Ewing's tumour – CD-99+.

Ginandroblastoma multiloculado, negativo para CD99 en una niña de 12 años: caso clínico / A twelve-years-old girl with multiloculated gynandroblastoma CD99 negative. Case report

Los ginandroblastomas son tumores del ovario extremadamente raros, los cuales comparten componentes de células de la granulosa y de células de Sertoli/Leydig. Se describe un caso de una niña de 12 años, quien presenta hemorragia uterina anormal y sensación de masa intraabdominal de crecimiento progresivo asociado a menorragia, niveles de CA-125 en 60,4 UI/mL y estudios de extensión que reportan masa quística en ovario izquierdo, manejada con ooforectomía. El estudio anatomopatológico muestra un tumor multiloculado lleno de material seroso, abundantes cuerpos de Call-Exner y 45% de células de Sertoli/Leydig. La inmunohistoquímica reveló inmunorreactividad para inhibina, calretinina y pCK, mientras que los marcadores CD99 y AE1/AE3 fueron negativos. Se trata del primer reporte de caso sobre un ginandroblastoma multiloculado, negativo para CD99 en una niña de 12 años, estudio que plantea un abordaje sistemático para los tumores de las células de los cordones sexuales.

The ginandroblastoma is an extremely rare ovarian tumor which shows components of granulosa cells and Sertoli/Leydig cells. We describe a case of a twelve-years-old girl who presented abnormal uterine bleeding and progressively growing intra- abdominal mass associated with menorrhagia, CA-125 60.4 UI/mL and extension studies reporting cystic mass in the left ovary. She underwent oophorectomy. Pathological study shows a multilocular tumor filled with serous material. Many Call-Exner bodies were observed in the histopathological analysis, 45% of Sertoli/Leydig cells. Immunohistochemistry was reactive for inhibin, calretinin and pCK while AE1/AE3 and CD99 markers were negative. This is the first case report about a multiloculated gynandroblastoma, negative for CD99 in a 12-years-old girl. Thus, the study of this clinical case represents a systematic approach for tumors of the sex cord cells.

Análise funcional de CD99 na tumorigênese de astrocitomas / Functional analysis of CD99 in astrocytomas tumorigenesis

Astrocitomas constituem o tipo mais comum de tumor cerebral neuroepitelial primário apresentando grande heteogeneidade. De acordo com a Organização Mundial de Saúde, os astrocitomas podem ser histologicamente divididos em graus I- IV. Astrocitomas pilocíticos (grau I) são tumores circunscritos, de crescimento lento e bom prognóstico. Astrocitomas difusos (grau II) apresentam hipercelularidade, crescimento relativamente lento e propensão para invadir o tecido cerebral normaladjacente. Astrocitomas anaplásicos (grau III) apresentam aumento da celularidade, atipia nuclear e figuras mitóticas. Glioblastomas (GBMs - grau IV) representam o mais frequente e maligno tumor cerebral humano com crescimento extremamente agressivo, anaplasia, células altamente proliferativas, com frequente neoangiogênese e necrose. O comportamento altamente invasivo dos GBMs, caracterizado pela infiltração difusa para o parênquima cerebral normal adjacente, inviabiliza a remoção cirúrgica total do tumor. Além disso, as células dos GBMs são relativamente resistentes às terapias disponíveis. Analogamente a outros tipos de câncer, os GBMs demonstram comportamentos semelhantes às de células trofoblásticas, sugerindo vias de sinalização compartilhadas no controle dos processos tumorigênicos e de implantação da placenta. Em ambos os casos, o estabelecimento de um fenótipo invasivo compreende processos celulares que incluem aumento da proliferação, expressão ou repressão de moléculas de adesão celular específicas, produção de enzimas que digerem a matriz extracelular, expressão de produtos de proto-oncogenes, ativação da telomerase, evasão ou edição da resposta imune do hospedeiro e angiogênese. Com base nas características comuns entre células tumorais e trofoblastos, o presente trabalho teve como objetivo a busca in silico de genes expressos em placenta e tecidos tumorais e que podem contribuir para o estabelecimento e manutenção do fenótipo maligno, utilizando os bancos de dados de MPSS e...

Astrocytomas are the most common type of primary neuroepithelial brain tumour and show great heterogeneity. According to World Health Organization criteria, astrocytomas can be histologically separated into grades I through IV. Pilocytic astrocytomas (grade I) are circumscribed, slow growing tumours with a good prognosis and mainly occur in children or young adults. Low-grade astrocytomas (grade II) show hypercellularity, relatively slow growth, and a propensity to invade surrounding normal brain tissue. Anaplastic astrocytomas (grade III) have increased cellularity, nuclear atypia, and mitotic figures. Glioblastomas (GBMs - grade IV), are the most common malignant and aggressive of all brain malignancies, exhibiting anaplastic, highly proliferative cells, with frequent neoangiogenesis and necrosis. GBM cells can escape complete resectability and are relatively resistant to the available therapies (radiation and chemotherapy). Similar to other cancer types, GBMs demonstrates behaviours that are analogous to trophoblastic cells, suggesting shared pathways to control tumourigenic processes and placental implantation. In both cases, the establishment of an invasive phenotype comprises cellular processes that include increased proliferation, the expression or repression of specific cell adhesion molecules, the production of enzymes that digest the extracellular matrix, the expression of proto-oncogene products, telomerase activation, evasion or edition of the host immune response, and angiogenesis. Based on the shared characteristics of tumour cells and trophoblasts, we searched in silico for genes that are in both placenta and tumour tissues using MPSS and SAGE databases and that could contribute to the establishment and maintenance of a malignant phenotype. Among 12 selected genes, CD99 exhibited the highest relative mRNA expression in GBM compared to non-neoplastic brain tissues. In a larger cohort of astrocytic tumours, we further demonstrated increased CD99...

Expression of CD99 in Multiple Myeloma: A Clinicopathologic and Immunohistochemical Study of 170 Cases

BACKGROUND: Multiple myeloma (MM) is a heterogeneous and ultimately fatal disease. Risk stratification using prognostic biomarkers is crucial to individualize treatments. We sought to investigate the role of CD99, a transmembrane protein highly expressed in many hematopoietic cells including subpopulations of normal and neoplastic plasma cells, for MM risk stratification. METHODS: CD99 expression was measured in paraffin samples of bone marrow and extramedullary biopsies of 170 patients with MM. Patients were divided into those with high score (moderately and strongly positive) and low score (negative and weakly positive), with all staining being cytoplasmic and/or membranous. RESULTS: High anti-CD99 immunostaining was observed in 72 of 136 (52.9%) bone marrow biopsies and 24 of 87 (27.6%) extramedullary biopsies in MM. High CD99 expression of extramedullary specimens was associated with significantly longer overall survival (OS; p=.016). High CD99 expression of extramedullary specimens was also associated with better prognosis in the nonautologous stem cell transplantation group of MM patients (p=.044). In multivariate analysis, International Staging System stage was an independent prognostic factor, whereas CD99 expression was no longer statistically significant. CONCLUSIONS: Expression of CD99 in extramedullary specimens was correlated with longer OS, suggesting that CD99 may be a helpful immunohistochemical marker for risk stratification.

The relationship between the expression of SHP1 and CD99 in Hodgkin lymphoma cell / 重庆医学

Objective To explore the relationship between SHP1 and CD99 expression in Hodgkin lymphoma (HL) .Methods RT‐PCR and Western blot to detect the expression of CD99 and SHP1 mRNA and protein expression in IM9、KM3、L428、L428‐CD99 cells ;fluorescence confocal to observe the expression and co‐localization of CD99 and SHP1 ;transiently interference CD99 in IM9 cells and then detect the expressing of SHP1 mRNA and protein levels .Results SHP1 mRNA was low expressed in L428、KM3 and high expressed in IM9;gene and protein expression were consistent trend;in L428‐CD99 cell SHP1 mRNA expression and protein levels were higher than L428 cell;CD99 expressed in membrane and SHP1 expressed in cell plasma;transient interference CD99 ,SHP1 decreased in mRNA expression and protein levels .Conclusion In HL cells ,SHP1 expression related to the missing expression of CD99 ,and its mechanism remains to be studied .

Central odontogenic fibroma: Report of case with immunohistochemical study.

Objectives: To report a case of central odontogenic fibroma (COF) with immunohistochemical study. Clinical Presentation: We describe a case of epithelium‑rich type of COF in the posterior region of the mandible of a 39‑year‑old woman. Immunohistochemical examination showed the odontogenic epithelium to be positive for high‑molecular‑weight cytokeratins, vimentin and CD99, and negative for CAM5.2. The stroma contained some myofibroblasts and many fibroblast‑like cells positive for CD99. Conclusion: Our immunohistochemical findings, and especially the positive expression of vimentin from the epithelial cells of COF suggests that these cells are primordial. Last but not least, the presence of a relative small number of myofibroblasts in the stroma justifies the non‑aggressive behavior of the neoplasm and supports that a part of stromal collagen of COF is produced by these cells.

Ewing's Sarcoma of the Lesser Sac Masquerading as a Pancreatic Tumor

Extraosseous Ewing's sarcoma/primitive neuroectodermal tumor (ES/PNET) is an uncommon, aggressive, and malignant tumor with a poor patient outcome. Its occurrence in the lesser sac is a rare event and to the best of our knowledge, has not been previously described. The present case was clinically and radiologically misdiagnosed as a pancreatic tumor/gastrointestinal stromal tumor. Histopathology revealed a tumor with "small round cells" that were positive for CD99, confirming the diagnosis of ES/PNET. This report highlights the importance of considering Ewing's sarcoma in the differential diagnosis of intraabdominal, extraintestinal masses.

Multiple Jejunal Myeloid Sarcomas Presenting with Intestinal Obstruction in a Non-leukemic Patient: A Case Report with Ultrastructural Observations

Myeloid sarcoma is a rare extramedullary myeloid tumor, which is frequently misdiagnosed when no evidence of leukemia is initially observed. Here, we report on a peculiar case of a 49-year-old man afflicted with multiple masses in the jejunum, the superior mesentery, and the serosa of the transverse colon, without leukemic manifestation. The tumor was composed of undifferentiated small round cells containing eosinophilic cytoplasm, which were negative for myeloperoxidase, nonspecific esterase, lysozyme, terminal deoxynucleotidyl transferase, leukocyte common antigen, CD3, CD4, CD15, CD20, CD30, CD43, CD56, CD68/PG-M1, CD79a, human melanoma black-45, c-kit, and CD34 with positivity only for CD68/KP1, CD99, and vimentin. Under electron microscopy, those cells had abundant membrane-bound cytoplasmic granules that measured 200 to 300 nm in diameter, which were consistent with granulocytic azurophilic granules. The tumor was finally diagnosed as a myeloid sarcoma. The presence of non-leukemic myeloid sarcomas showing immunonegativity for conventional myeloid-leukemic markers necessitated a diagnosis by ultrastructural observation.