Objective:This study investigated the underlying causes of discordance between multiplex fluorescence polymerase chain reaction (PCR)-capillary electrophoresis in determining MSI and immunohistochemistry (IHC) for mismatch repair (MMR) protein evaluation in gastrointestinal adenocarcinomas, aiming to improve interpretation accuracy and guide clinical precision treatment strategies.Methods:A retrospective analysis was conducted on 511 surgically resected or biopsied specimens (161 gastric adenocarcinomas and 350 colorectal adenocarcinomas) diagnosed at the Department of Pathology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine from January to June 2024. MMR protein expression of tumors was evaluated by IHC, while MSI status was assessed using the 2B3D National Cancer Institute (NCI) Panel through multiplex fluorescence PCR-capillary electrophoresis on tumor DNA and matched normal DNA. The concordance between the two methods was analyzed, and factors contributing to the discordance were investigated. Cases with unstable dinucleotide loci only in the 2B3D NCI Panel, focal MMR protein loss, or unexplained discrepancies underwent validation using the non-NCI Panel through multiplex fluorescence PCR-capillary electrophoresis markers or next-generation sequencing (NGS).Results:In the 511 gastrointestinal adenocarcinomas, the results of the two methods were discordant in 15 cases (2.9%), with a significantly higher discordantrate in gastric cancers (7.5%, 12/161) compared to colorectal cancers (0.9%, 3/350; P＜0.001). Key contributors to the discordance included: sampling limitations (6 cases), 2B3D NCI Panel design constraints (3 cases),tumor heterogeneity (3 cases),isolated MSH6 deficiency (1 case),and unexplained discrepancies (2 cases).Validation studies demonstrated that cases with dinucleotide-only instability showed concordance with IHC after using the non-NCI Panel through multiplex fluorescence PCR-capillary electrophoresis and NGS verifications. Specimens with focal MMR protein loss and unexplained discrepancies aligned with initial PCR results upon NGS validation. Unexplained cases harbored Kirsten rat sarcoma class Ⅰ variants and multiple class Ⅱ genetic alterations. Conclusions:Colorectal adenocarcinoma demonstrated higher concordance between PCR-capillary electrophoresis and IHC than gastric adenocarcinoma.Discordant results require systematic evaluation including technical review, specimen quality control, and supplemental NGS analysis to resolve discrepancies.

Purpose To investigate the clinical features of gastrointestinal leiomyomas(GLs)with scattered ex-pression of CD117 and DOG1,and to evaluate their biological behavior as well as their different diagnositic value from gastrointestinal stromal tumors(GISTs).Methods Clinical data from 17 cases of surgically resected GLs were col-lected.Immunohistochemistry using the EnVision method was performed to detect SMA,desmin,h-caldesmon,DOG1,CD117,and CD34.First-generation sequencing was performed to analyze exons 9-20 of the KIT gene and ex-ons 12 and 18 of the PDGFRA gene.Results Tumors occured in the stomach(8 cases)and esophagus(9 cases).Clinical manifestations included dull upper abdominal pain,dysphagia,chest pain,and fever.During a follow-up peri-od of 58-88 months,no recurrence was observed,and all patients had a favorable prognosis.Histologically,tumor cells were spindle-shaped and arranged in bundles or a woven pattern.Interstitial cells of Cajal appeared spindle-shaped or stellate with indistinct borders and dispersed chromatin.Tumor cells showed diffuse positivity for SMA,desmin,and h-caldesmon(100％).Interstitial cells of Cajal exhibited focal positive for CD117 and DOG1,with an o-verall positive rate of 9％for each marker.No pathogenic mutations of the KIT or PDGFRA genes were detected by first-generation sequencing.Conclusion Although some GLs contained interstitial cells of Cajal that showed focal pos-itivity for CD117 and DOG1,sequencing and long-term follow-up confirmed that their biological behavior differed from that of GISTs,with no malignant potential.Surgical resection remained the mainstay of treatment,and the prognosis was favorable.

Objective:To investigate the clinicopathological and genetic characteristics of monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL).Methods:The forty-two MEITL cases diagnosed in the Department of Pathology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China from 2016 to 2022 was retrospectively analyzed. Clinical data were collected, and follow-up was performed. Morphological characteristics were observed. Immunohistochemistry, Epstein-Barr virus (EBV) in situ hybridization, clonal rearrangement analysis of T-cell receptor (TCR) genes, and targeted next-generation sequencing (NGS) were performed.Results:Among the 42 patients (male/female ratio of 2.8∶1.0), the age range was 32-77 years with a median age of 59.5 (52.0-65.0) years. Grossly, the tumors were presented as ulcerative or exophytic lesions, with a maximum diameter of 2-18 cm. There were 34 cases with a single lesion and 8 cases with more than 1 lesion. The tumor cells in all 42 cases were relatively monotonous in histology and small or medium in size. They had round or oval nuclei, moderately pale or clear cytoplasm, evenly distributed nuclear chromatin, inconspicuous nucleoli, and frequent mitotic figures. In one of the cases, there were moderately large cells, vacuolated nuclei, and clear nucleoli. Lymphoepithelial lesions were observed in 36 (85.7%) of the 42 cases, tumor necrosis in 4 (9.5%) cases, scattered eosinophils and/or plasma cell infiltration in the background in 9 (21.4%) cases, and a "starry sky" phenomenon in 1 (2.4%) case. The tumor cells in all cases exhibited high expression of CD3, CD2, CD7, CD8, CD56, TIA1, Granzyme B, and Perforin, while some also expressed CD4 (5/41, 12.2%), CD5 (3/41, 7.3%), CD20 (4/41, 11.9%), CD79α (2/37, 5.4%), and CD30 (1/34, 2.9%). The Ki-67 proliferation index ranged from 40% to 90%. EBER in situ hybridization tests were negative in all cases. TCR gene clonal rearrangement was detected in 96.4% (27/28) of the tested cases. Targeted NGS revealed commonly mutated genes including SETD2, STAT5B, JAK3, TP53, and CREBBP. The primary treatment was chemotherapy, with 2 cases undergoing autologous hematopoietic stem cell transplantation. Follow-up information was obtained for 29 cases, with a follow-up period of 1-73 months. The mortality was 93.1% (27/29).Conclusions:MEITL is a rare and highly aggressive peripheral T-cell lymphoma. Its clinical manifestations are diverse, and diagnosis primarily relies on a comprehensive assessment of pathological morphology, immunohistochemical profiles, and EBV infection status, supplemented by genetic testing if necessary. At present, there is no effective treatment, and its overall prognosis is poor.

Objective:To investigate the incidence of mild cognitive impairment(MCI)and malnutrition among centenarians, as well as to explore the relationship between cognitive impairment and nutritional status.Methods:A cross-sectional study was conducted between November and December 2023, involving 121 elderly individuals aged ≥ 100 years in the Baoshan District of Shanghai.The survey collected general information and included the Ascertain Dementia 8-item Questionnaire(AD8), the Mini Nutritional Assessment Short-Form(MNA-SF), and anthropometric nutritional measurements such as waist circumference(WC), hip circumference(HC), arm circumference(AC), calf circumference(CC), and grip strength.The prevalence of MCI and malnutrition among centenarians was calculated, and the correlation between MCI and MNA-SF scores, along with anthropometric nutritional measurement indicators, was analyzed.Results:The age range of centenarians was between 100 and 105 years, with an average age of 101.0±3.5 years.The majority of centenarians were female(76.9%), illiterate(58.7%), and lived with family members(73.6%).All participants had medical insurance(100%).Most had no history of long-term smoking 118(97.5%), long-term alcohol consumption 108(89.3%), long-term use of health supplements 109(90.1%), long-term tea or coffee habits 114(94.2%), chronic medical conditions 84(69.4%), or family history of dementia 102(84.3%).Additionally, 62(51.2%)reported their health status over the past year as general.According to the AD8 screening results, the negative and positive detection rates of MCI in centenarians were 79(65.3%)and 47(34.7%), respectively.Based on the MNA-SF scoring results, the detection rates of normal nutrition, malnutrition risk, and malnutrition among centenarians were 36(29.8%), 61(50.4%), and 24(19.8%), respectively.There was a statistically significant difference in AC between the non-MCI group and the MCI group among centenarians( t=0.01, P=0.03).The AD8 scores of centenarians were significantly negatively correlated with AC, CC, and MNA-SF scores( r=-0.20, r=-0.26, r=-0.29; all P<0.05). Conclusions:The cognitive function of centenarians is associated with their nutritional status, indicating that higher cognitive abilities correlate with better nutritional status.

Purpose To investigate the clinicopathological features and prognosis of adult large B-cell lymphoma with IRF4 rearrangement(LBCL-IRF4r).Methods Clinical data of 63 adult LBCL-IRF4r cases were collected.The EnVision two-step method was employed for immunohistochemical staining,and fluorescence in situ hybridization was used to detect rearrangements or deletions of the IRF4,BCL2,MYC,BCL6,and TP53 genes.The relationship be-tween clinicopathological features and prognosis was analyzed and compared with data from 132 adult non-specified dif-fuse large B-cell lymphoma(DLBCL)cases.Results Among the 63 adult LBCL-IRF4r patients,the male to female ratio was 1.1∶1,with a median age of 54.0 years(range 20-84 years),and 14 cases(22.2％)were＜40 years old,24 cases(38.1％)were between 40 and 60 years old,and 25 cases(39.7％)were＞60 years old.18 cases(28.6％)were involved in Waldeyer's ring,along with 8 cases(12.7％)in cervical lymph nodes,7 cases(11.1％)in other lymph nodes and lymphatic organs,13 cases(20.6％)in stomach,4 cases(6.4％)in intestine,and 13 cases(20.6％)in other extranodal sites.63 cases showed IRF4 rearrangements,with no BCL2 and MYC translocations(0/58),30.9％(17/55)had BCL6 translocations,and 16.3％(8/49)had TP53 deletions.59 pa-tients were followed up for a median of 28 months(range 1-65 months).48 patients(81.4％)achieved complete re-sponse,10 patients(16.9％)experienced disease progression or relapse,and 3 patients(5.1％)died.Univariate a-nalysis showed that lactate dehydrogenase level,Ann Arbor stage,international prognostic index(IPI)score,growth pattern,Hans classification,and double expression of BCL2 and C-MYC were significantly associated with progression-free survival.Age,Ann Arbor stage,and IPI score were significantly associated with overall survival.Multivariate Cox regression analysis showed that double expression of BCL2 and C-MYC was an independent prognostic factor for pro-gression-free survival.Adult LBCL-IRF4r had significantly higher complete response rate and progression-free survival than adult DLBCL.Conclusion LBCL-IRF4r occurs in adults of all age groups,commonly affecting Waldeyer's ring,cervical lymph nodes,and gastrointestinal tract,and has a favorable clinical prognosis.

Purpose To investigate the clinical,imaging,and pathological features of Kikuchi-Fujimoto disease(KFD).Methods A retrospective analysis was conducted on 123 pathologically confirmed KFD cases.Clinical and imaging data were collected,and histopathological features were evaluated using HE staining,immunohistochemistry,in situ hybridization for EBER,and molecular analyses(TCR/Ig gene rearrangements by PCR with capillary electro-phoresis).Results Among the 123 patients,the male-to-female ratio was 1∶2,with a median age of 30 years.All patients presented with lymphadenopathy.Among 30 hospitalized patients,63.3％(19/30)had fever,and 23.3％(7/30)had concurrent autoimmune diseases.Of the 12 patients who underwent PET-CT,91.7％(11/12)were sus-pected of malignancy,prompting biopsy recommendations.Among 47 consultation cases,27.7％(13/47)were ini-tially misdiagnosed as lymphoma.Histopathological examination revealed proliferative,necrotic,and xanthomatous phases,which coexisted or occurred independently.The proliferative phase was characterized by atypical lymphocytes and histiocytes,the necrotic phase by abundant eosinophilic fibrin deposits and nuclear debris,and the xanthomatous phase by clusters of foam-like histiocytes.Immunohistochemically analyses revealed that atypical lymphocytes were neg-ative for CD20,CD4,and CD56 but positive for CD3,CD8,TIA1,Granzyme B,and Perforin.Histiocytes expressed CD68,CD163,and MPO,while CD123-positive plasmacytoid dendritic cells were predominantly located around the le-sions and blood vessels.EBER was positive in individual cells in 4 cases.TCR gene rearrangement was positive in 2 cases and suspected positive in 3 cases,while Ig rearrangement was positive and suspected positive in 1 case each.Conclusion KFD exhibits clinical,imaging,and pathological features that can mimic lymphoma,highlighting the im-portance of accurate diagnosis to avoid misdiagnosis and inappropriate treatment.

Purpose To investigate the clinicopathological features and prognosis of adult large B-cell lymphoma with IRF4 rearrangement(LBCL-IRF4r).Methods Clinical data of 63 adult LBCL-IRF4r cases were collected.The EnVision two-step method was employed for immunohistochemical staining,and fluorescence in situ hybridization was used to detect rearrangements or deletions of the IRF4,BCL2,MYC,BCL6,and TP53 genes.The relationship be-tween clinicopathological features and prognosis was analyzed and compared with data from 132 adult non-specified dif-fuse large B-cell lymphoma(DLBCL)cases.Results Among the 63 adult LBCL-IRF4r patients,the male to female ratio was 1.1∶1,with a median age of 54.0 years(range 20-84 years),and 14 cases(22.2％)were＜40 years old,24 cases(38.1％)were between 40 and 60 years old,and 25 cases(39.7％)were＞60 years old.18 cases(28.6％)were involved in Waldeyer's ring,along with 8 cases(12.7％)in cervical lymph nodes,7 cases(11.1％)in other lymph nodes and lymphatic organs,13 cases(20.6％)in stomach,4 cases(6.4％)in intestine,and 13 cases(20.6％)in other extranodal sites.63 cases showed IRF4 rearrangements,with no BCL2 and MYC translocations(0/58),30.9％(17/55)had BCL6 translocations,and 16.3％(8/49)had TP53 deletions.59 pa-tients were followed up for a median of 28 months(range 1-65 months).48 patients(81.4％)achieved complete re-sponse,10 patients(16.9％)experienced disease progression or relapse,and 3 patients(5.1％)died.Univariate a-nalysis showed that lactate dehydrogenase level,Ann Arbor stage,international prognostic index(IPI)score,growth pattern,Hans classification,and double expression of BCL2 and C-MYC were significantly associated with progression-free survival.Age,Ann Arbor stage,and IPI score were significantly associated with overall survival.Multivariate Cox regression analysis showed that double expression of BCL2 and C-MYC was an independent prognostic factor for pro-gression-free survival.Adult LBCL-IRF4r had significantly higher complete response rate and progression-free survival than adult DLBCL.Conclusion LBCL-IRF4r occurs in adults of all age groups,commonly affecting Waldeyer's ring,cervical lymph nodes,and gastrointestinal tract,and has a favorable clinical prognosis.

Purpose To investigate the clinical,imaging,and pathological features of Kikuchi-Fujimoto disease(KFD).Methods A retrospective analysis was conducted on 123 pathologically confirmed KFD cases.Clinical and imaging data were collected,and histopathological features were evaluated using HE staining,immunohistochemistry,in situ hybridization for EBER,and molecular analyses(TCR/Ig gene rearrangements by PCR with capillary electro-phoresis).Results Among the 123 patients,the male-to-female ratio was 1∶2,with a median age of 30 years.All patients presented with lymphadenopathy.Among 30 hospitalized patients,63.3％(19/30)had fever,and 23.3％(7/30)had concurrent autoimmune diseases.Of the 12 patients who underwent PET-CT,91.7％(11/12)were sus-pected of malignancy,prompting biopsy recommendations.Among 47 consultation cases,27.7％(13/47)were ini-tially misdiagnosed as lymphoma.Histopathological examination revealed proliferative,necrotic,and xanthomatous phases,which coexisted or occurred independently.The proliferative phase was characterized by atypical lymphocytes and histiocytes,the necrotic phase by abundant eosinophilic fibrin deposits and nuclear debris,and the xanthomatous phase by clusters of foam-like histiocytes.Immunohistochemically analyses revealed that atypical lymphocytes were neg-ative for CD20,CD4,and CD56 but positive for CD3,CD8,TIA1,Granzyme B,and Perforin.Histiocytes expressed CD68,CD163,and MPO,while CD123-positive plasmacytoid dendritic cells were predominantly located around the le-sions and blood vessels.EBER was positive in individual cells in 4 cases.TCR gene rearrangement was positive in 2 cases and suspected positive in 3 cases,while Ig rearrangement was positive and suspected positive in 1 case each.Conclusion KFD exhibits clinical,imaging,and pathological features that can mimic lymphoma,highlighting the im-portance of accurate diagnosis to avoid misdiagnosis and inappropriate treatment.

Purpose To investigate the clinical features of gastrointestinal leiomyomas(GLs)with scattered ex-pression of CD117 and DOG1,and to evaluate their biological behavior as well as their different diagnositic value from gastrointestinal stromal tumors(GISTs).Methods Clinical data from 17 cases of surgically resected GLs were col-lected.Immunohistochemistry using the EnVision method was performed to detect SMA,desmin,h-caldesmon,DOG1,CD117,and CD34.First-generation sequencing was performed to analyze exons 9-20 of the KIT gene and ex-ons 12 and 18 of the PDGFRA gene.Results Tumors occured in the stomach(8 cases)and esophagus(9 cases).Clinical manifestations included dull upper abdominal pain,dysphagia,chest pain,and fever.During a follow-up peri-od of 58-88 months,no recurrence was observed,and all patients had a favorable prognosis.Histologically,tumor cells were spindle-shaped and arranged in bundles or a woven pattern.Interstitial cells of Cajal appeared spindle-shaped or stellate with indistinct borders and dispersed chromatin.Tumor cells showed diffuse positivity for SMA,desmin,and h-caldesmon(100％).Interstitial cells of Cajal exhibited focal positive for CD117 and DOG1,with an o-verall positive rate of 9％for each marker.No pathogenic mutations of the KIT or PDGFRA genes were detected by first-generation sequencing.Conclusion Although some GLs contained interstitial cells of Cajal that showed focal pos-itivity for CD117 and DOG1,sequencing and long-term follow-up confirmed that their biological behavior differed from that of GISTs,with no malignant potential.Surgical resection remained the mainstay of treatment,and the prognosis was favorable.

Objective:To investigate the clinicopathological and genetic characteristics of monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL).Methods:The forty-two MEITL cases diagnosed in the Department of Pathology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China from 2016 to 2022 was retrospectively analyzed. Clinical data were collected, and follow-up was performed. Morphological characteristics were observed. Immunohistochemistry, Epstein-Barr virus (EBV) in situ hybridization, clonal rearrangement analysis of T-cell receptor (TCR) genes, and targeted next-generation sequencing (NGS) were performed.Results:Among the 42 patients (male/female ratio of 2.8∶1.0), the age range was 32-77 years with a median age of 59.5 (52.0-65.0) years. Grossly, the tumors were presented as ulcerative or exophytic lesions, with a maximum diameter of 2-18 cm. There were 34 cases with a single lesion and 8 cases with more than 1 lesion. The tumor cells in all 42 cases were relatively monotonous in histology and small or medium in size. They had round or oval nuclei, moderately pale or clear cytoplasm, evenly distributed nuclear chromatin, inconspicuous nucleoli, and frequent mitotic figures. In one of the cases, there were moderately large cells, vacuolated nuclei, and clear nucleoli. Lymphoepithelial lesions were observed in 36 (85.7%) of the 42 cases, tumor necrosis in 4 (9.5%) cases, scattered eosinophils and/or plasma cell infiltration in the background in 9 (21.4%) cases, and a "starry sky" phenomenon in 1 (2.4%) case. The tumor cells in all cases exhibited high expression of CD3, CD2, CD7, CD8, CD56, TIA1, Granzyme B, and Perforin, while some also expressed CD4 (5/41, 12.2%), CD5 (3/41, 7.3%), CD20 (4/41, 11.9%), CD79α (2/37, 5.4%), and CD30 (1/34, 2.9%). The Ki-67 proliferation index ranged from 40% to 90%. EBER in situ hybridization tests were negative in all cases. TCR gene clonal rearrangement was detected in 96.4% (27/28) of the tested cases. Targeted NGS revealed commonly mutated genes including SETD2, STAT5B, JAK3, TP53, and CREBBP. The primary treatment was chemotherapy, with 2 cases undergoing autologous hematopoietic stem cell transplantation. Follow-up information was obtained for 29 cases, with a follow-up period of 1-73 months. The mortality was 93.1% (27/29).Conclusions:MEITL is a rare and highly aggressive peripheral T-cell lymphoma. Its clinical manifestations are diverse, and diagnosis primarily relies on a comprehensive assessment of pathological morphology, immunohistochemical profiles, and EBV infection status, supplemented by genetic testing if necessary. At present, there is no effective treatment, and its overall prognosis is poor.