[Prognostic performance of pulmonary effective arterial elastance in patients with heart failure].

Objective: To explore the predictive value of pulmonary effective arterial elastance (Ea) in patients with heart failure (HF). Methods: This is a retrospective cohort study, which retrospectively included 284 patients with HF who underwent right heart catheterization at Heart Failure Center in Fuwai Hospital between September 2013 and February 2022. Data regarding baseline clinical characteristics, hemodynamic profiles, and prognosis were collected. Ea was calculated as mean pulmonary arterial pressure/stroke volume. Patients were divided into Ea<0.555 group and Ea≥0.555 group according to the median value of Ea (0.555 mmHg/ml, 1 mmHg=0.133 kPa). The primary outcome was the primary clinical event, set as the first occurrence of a series of composite events, including all-cause death, heart transplantation, left ventricular assist device implantation, and HF rehospitalization. Event-free survival was defined as the absence of primary clinical events. Spearman correlation analysis was used to calculate the correlation coefficient between Ea and parameters reflective of right heart function. The Kaplan-Meier analysis was used to compare the different groups for the estimation of outcomes with the log-rank test. We used Cox proportional-hazards regression models to estimate hazard ratios (HR) for primary clinical event. Subgroup analysis was performed based on the age, gender, New York Heart Association (NYHA) functional class, left ventricular ejection fraction, presence of pulmonary hypertension, and serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) values. We used receiver operating characteristic (ROC) curve to calculate the area under the curve (AUC) of Ea for predicting event-free survival in patients with HF. Results: The median age was 51 years, and 206 (72.5%) patients were male. Ea and pulmonary vascular resistance (PVR) were significantly correlated (r=0.698, P<0.001). The correlation between Ea and pulmonary arterial elastance (PAC) were even more significant (r=-0.888, P<0.001). Compared with Ea<0.555 group, Ea≥0.555 group presented with higher serum NT-proBNP values (4 443 (1 792, 8 554) ng/L vs. 1 721 (480, 4 528)ng/L,P<0.001), higher PVR (3.4 (2.5, 4.7) Wood vs. 1.4 (0.9, 2.2) Wood, P<0.001), lower cardiac output (3.0 (2.3, 3.9) L/min vs. 4.3 (3.8, 4.9) L/min, P<0.001), and lower PAC (1.6 (1.3, 2.0) ml/mmHg vs. 4.0 (3.0, 6.0) ml/mmHg, P<0.001). The median follow-up time was 392 (166, 811) days. The Kaplan-Meier survival curve demonstrated a lower event-free survival rate in the Ea≥0.555 group compared to the Ea<0.555 group (Plog-rank<0.001). After multivariate adjustment, Ea (HR=1.734, P<0.001) remained significantly associated with the primary outcome. Subgroup analysis indicated that Ea was associated with the primary outcome across all subgroups. The AUC was 0.724 (P<0.001) for Ea to predict event-free survival calculated from ROC analysis. Conclusions: Ea is closely related to parameters reflective of right ventricular afterload. Increased Ea is an independent predictor of adverse outcomes in patients with HF.

[A multicenter prospective study on early identification of refractory Mycoplasma pneumoniae pneumonia in children].

Objective: To explore potential predictors of refractory Mycoplasma pneumoniae pneumonia (RMPP) in early stage. Methods: The prospective multicenter study was conducted in Zhejiang, China from May 1st, 2019 to January 31st, 2020. A total of 1 428 patients with fever >48 hours to <120 hours were studied. Their clinical data and oral pharyngeal swab samples were collected; Mycoplasma pneumoniae DNA in pharyngeal swab specimens was detected. Patients with positive Mycoplasma pneumoniae DNA results underwent a series of tests, including chest X-ray, complete blood count, C-reactive protein, lactate dehydrogenase (LDH), and procalcitonin. According to the occurrence of RMPP, the patients were divided into two groups, RMPP group and general Mycoplasma pneumoniae pneumonia (GMPP) group. Measurement data between the 2 groups were compared using Mann-Whitney U test. Logistic regression analyses were used to examine the associations between clinical data and RMPP. Receiver operating characteristic (ROC) curves were used to analyse the power of the markers for predicting RMPP. Results: A total of 1 428 patients finished the study, with 801 boys and 627 girls, aged 4.3 (2.7, 6.3) years. Mycoplasma pneumoniae DNA was positive in 534 cases (37.4%), of whom 446 cases (83.5%) were diagnosed with Mycoplasma pneumoniae pneumonia, including 251 boys and 195 girls, aged 5.2 (3.3, 6.9) years. Macrolides-resistant variation was positive in 410 cases (91.9%). Fifty-five cases were with RMPP, 391 cases with GMPP. The peak body temperature before the first visit and LDH levels in RMPP patients were higher than that in GMPP patients (39.6 (39.1, 40.0) vs. 39.2 (38.9, 39.7) ℃, 333 (279, 392) vs. 311 (259, 359) U/L, both P<0.05). Logistic regression showed the prediction probability π=exp (-29.7+0.667×Peak body temperature (℃)+0.004×LDH (U/L))/(1+exp (-29.7+0.667×Peak body temperature (℃)+0.004 × LDH (U/L))), the cut-off value to predict RMPP was 0.12, with a consensus of probability forecast of 0.89, sensitivity of 0.89, and specificity of 0.67; and the area under ROC curve was 0.682 (95%CI 0.593-0.771, P<0.01). Conclusion: In MPP patients with fever over 48 to <120 hours, a prediction probability π of RMPP can be calculated based on the peak body temperature and LDH level before the first visit, which can facilitate early identification of RMPP.

Airway Reactance Predicts Static Lung Hyperinflation in Severe Asthma.

BACKGROUND AND OBJECTIVES: Background: Static lung hyperinflation (SLH) measured using body plethysmography in patients with asthma is associated with poor outcomes. The severity of SLH may be associated with small airway dysfunction (SAD), which can be measured using impulse oscillometry (IOS). Objective: This study aims to determine the correlation between SLH and SAD in patients with severe asthma and assess the improvement in SLH and SAD with treatment. METHODS: We analyzed data from patients who were enrolled in the Taiwan Severe Asthma Registry, which comprises a prospective observational cohort. Plethysmography and IOS were performed regularly. The relationship between spirometry and IOS parameters was determined. Changes in the clinical outcomes in response to treatment were analyzed. RESULTS: Of 107 patients with severe asthma, 83 (77.6%) had SLH based on an increased residual volume to total lung capacity ratio (RV/ TLC). Most patients were older women with worse pulmonary function and SAD than those without SLH. SAD, defined as increased airway resistance/reactance, was significantly correlated with SLH. Airway reactance at 5 Hz (X5) ≤-0.21 kPa/(L/s) detected SLH with an area under the receiver operating characteristic curve of 0.84 (P<.0001; sensitivity, 85.2%; and specificity, 83.3%). After 12 months, patients who received add-on biologics (vs those who did not) had significantly reduced exacerbations, fractional exhaled nitric oxide level, and blood eosinophil counts, as well as improved forced expiratory volume in the first second, X5, and a trend toward reduced RV/TLC ratio. CONCLUSIONS: In severe asthma, airway reactance (X5) could be a novel parameter for assessing SLH.

[Diagnosis and orthodontic treatment strategy of complete canine transposition].

Tooth transposition is a challenge for orthodontists, especially in correcting the order of teeth. At present, the literature on transposition canines mainly focuses on epidemiological studies and case reports, and no systematic treatment guidance has been formed. In this article, the definition and classification, epidemiology and etiology, imaging diagnosis, treatment and risk control of transposed canines are systematically described in order to provide reference for clinical practice.

[Association between serum potassium levels and all-cause mortality in patients with acute heart failure].

Objective: To investigate the relationship between different serum potassium levels at admission and discharge and all-cause mortality in patients with acute heart failure (HF). Methods: A total of 2 621 patients with acute HF who were hospitalized in the Heart Failure Center of Fuwai Hospital from October 2008 to October 2017 were analyzed. Patients were divided into three groups according to the different serum potassium levels at admission: hypokalemia with serum potassium<3.5 mmol/L (n=329), normokalemia with 3.5-5.5 mmol/L (n=2 270), and hyperkalemia with serum potassium>5.5 mmol/L (n=22). Clinical data such as patient history, comorbidities, clinical examination and drug use were collected, and systematic outpatient review or telephone follow-up was performed after patients were discharged from the hospital until January 2020. The primary outcome was all-cause death at 90 days, 2 years, and 5 years of follow-up. We compared the clinical characteristics of patients with different serum potassium levels at admission and discharge, and used a multivariate Cox proportional hazards regression model to analyze the association between serum potassium levels at admission and discharge and all-cause mortality. Results: The age of all patients was (58.0±15.3) years old, and 1 877 patients (71.6%) were male. There were 329 (12.6%) and 22 (0.8%) patients with hypokalemia and hyperkalemia at admission, and 38 (1.4%) and 18 (0.7%) at discharge, respectively. The serum potassium levels of all patients were (4.01±0.50) and (4.25±0.44) mmol/L at admission and discharge, respectively. The follow-up time[M(Q1,Q3)] of this study was 2.63(1.00,4.42)years, and a total of 1 076 all-cause deaths were recorded at the last follow-up. Compared with patients with normokalemia at discharge, discharged patients with hypokalemia and hyperkalemia were followed up for 90 days (90.3% vs 76.3% vs 38.9%), 2 years (73.8% vs 60.5% vs 33.3%) and 5 years (63.4% vs 44.7% vs 22.2%), respectively, and the difference of which in cumulative survival rates were statistically significant (all P values<0.001). The multivariate-adjusted Cox regression analysis showed that hypokalemia (HR=0.979, 95%CI: 0.812-1.179, P=0.820) and hyperkalemia (HR=1.368, 95%CI: 0.805-2.325, P=0.247) at admission were not associated with all-cause mortality risk, however, hypokalemia (HR=1.668, 95%CI: 1.081-2.574, P=0.021) and hyperkalemia (HR=3.787, 95%CI: 2.264-6.336, P<0.001) at discharge were associated with increased all-cause mortality risk. Conclusions: Both hypokalemia and hyperkalemia at discharge in hospitalized patients with acute HF were associated with increased short-and long-term all-cause mortality, and serum potassium levels should be closely monitored.

[Construction of IPA decision model for diabetes prevention and control based on economy and importance].

Objective: To determine the priority of diabetes prevention and control measures in the perspective of the economy and importance, and provide theoretical support for guiding relevant departments to implement measures based on actual economic level. Methods: An online survey was conducted on the importance, feasibility and implementation of major chronic disease prevention and control measures in 488 national demonstration areas for comprehensive chronic disease prevention and control. The content of the survey was divided into individual and group levels, with 10 dimensions and 44 measures, to obtain the scores of the economy and importance. IPA model was used to divide the dimension index of diabetes prevention and control into quadrants. The standardized factor load coefficient of the second-order confirmatory factor analysis was used to determine the priority of dimension index in the same quadrant. The priority of prevention and control measures in each dimension was determined by the discriminant parameter of project response theory. Results: The mean scores of economy and importance were 66.50 and 89.94, respectively, and the matrix was divided into four quadrants. The first quadrant was the "highest priority" with high importance and economy, including medical insurance and family doctors, health education, high-risk detection and intervention, patient management and community action. The second quadrant was characterized as high importance but low economy, which was the priority for improvement, including only one dimension of complication screening. The third quadrant was the lowest priority due to low importance and economy, including personal health service evaluation and follow-up, environmental support, diabetes co-infection prevention and glycemic policy. The last quadrant had low importance but high economy, which was the second improvement level. The priority measures in different quadrants were: (1) the highest priority: blood lipid control, occupational site, prevention and control work plan, blood glucose testing, family doctor contract service; (2) the priority improvement: annual neuropathy screening; (3)the lowest priority: universal access to risk scoring, healthy eating, healthy dining innovations and tuberculosis screening. Conclusion: IPA model can be used to construct a decision-making model for diabetes prevention and control and determine the priority of corresponding measures.

Impact of different subspecies on disease progression in initially untreated patients with Mycobacterium avium complex lung disease.

OBJECTIVE: Disease progression is a strong indicator of treatment for Mycobacterium avium complex lung disease (MAC-LD). The impact of MAC subspecies on the risk of disease progression remains uncertain in MAC-LD patients. METHODS: In this cohort study, we included MAC-LD patients from 2013 to 2018 and classified them into M. intracellulare, M. avium, M. chimaera and other subspecies groups by genotype. We observed the disease progression of MAC-LD, indicated by antibiotic initiation and/or radiographic progression. We used Cox regression analysis to assess predictors for disease progression. RESULTS: Of 105 MAC isolates from unique MAC-LD patients, 35 (33%) were M. intracellulare, 41 (39%) M. avium, 16 (15%) M. chimaera and 13 (12%) other subspecies. After a mean follow-up time of 1.3 years, 56 (53%) patients developed disease progression: 71% (25/35), 54% (22/41), 31% (4/13) and 31% (5/16) in patients with M. intracellulare, M. avium, others and M. chimaera, respectively. The independent predictors for disease progression were M. chimaera subspecies (HR 0.356, 95% CI (0.134-0.943)), compared with the reference group of M. intracellulare, body mass index ≤20 kg/m2 (HR 1.788 (1.022-3.130)) and initial fibrocavitary pattern (HR 2.840 (1.190-6.777)) after adjustment for age, sex and sputum smear positivity. Among patients without fibrocavitary lesions (n = 94), the risk of disease progression significantly decreased in patients with other subspecies (HR 0.217 (0.050-0.945)) and remained low in those with M. chimaera (HR 0.352 (0.131-0.947)). CONCLUSIONS: Mycobacterium chimaera was not uncommon in this study; unlike M. intracellulare, it was negatively correlated with disease progression of MAC-LD, suggesting a role of MAC subspecies identification in prioritizing patients.

[Expression of p-AKT and p-mTOR in pediatric Burkitt lymphoma and their correlation with prognosis].

Objective: To evaluate the expression of p-AKT and p-mTOR, the key proteins in PI3K/AKT/mTOR pathway in pediatric Burkitt lymphoma (BL), and to investigate the clinical and prognostic significance. Methods: Fifty-eight cases of pediatric BL and thirty cases of reactive hyperplastic lymphadenitis (RH) were collected at Children's Hospital of Fudan University from September 2011 to July 2018. Paraffin sections of tissues were immune stained for p-AKT and p-mTOR, and the expression was assessed and correlated with the clinical features and prognosis. Results: A total of 58 cases were diagnosed and 6 cases lost the follow-up. Of the remaining 52 BL patients including 43 males and 9 females, the median age was 5 years (range: 2 to 14 years). Regarding to the correlation between the two biomarkers, Spearman test showed that p-mTOR was positively associated with the expression of p-AKT (r=0.759, P<0.001). Of all BL patients, the positive rates of p-AKT and p-mTOR were 62.1% (36/58) and 60.3%(35/58) respectively, both significantly higher than control group (P=0.011, P=0.035 respectively). The presence of p-AKT was significantly associated with higher lactate dehydrogenase (LDH≥573 IU/L) level in patients of the disease (P=0.006), while p-mTOR was increased both in the higher LDH and lower ratio of albumin to globulin (A/G) group (P=0.006, P=0.034 respectively). Expression of p-AKT and p-mTOR did not show any statistical correlation with sex, age, St.jude stage, tumor size, B-symptom present or not, number of extra-nodal sites or international prognostic index (IPI) (P>0.05). Fifty-two patients had a median follow-up of 40 months (range: 5-87 months). Univariate analysis showed that p-AKT expression was significant in predicting both inferior OS (5-year estimate, 72.7% vs. 94.7%, χ(2)=4.123, P=0.042) and PFS (5-year estimate, 66.7% vs. 94.7%, χ(2)=5.822, P=0.016). The 5-year OS rate was 71.0% (22/31) for the p-mTOR positive cohort of patients compared to 95.2% (17/21) for p-mTOR negative group (χ(2)=4.881, P=0.027); however, there was no statistical significance in 5-year PFS rate (P>0.05). Especially, the 5-year OS and PFS rate of p-AKT/p-mTOR double-positive group were significantly lower than negative control group (including absence of single p-AKT or p-mTOR expression, and absence of both) (OS: 69.0% vs. 95.7%, χ(2)=6.285, P=0.012; PFS: 65.5% vs. 91.3%, χ(2)=5.405, P=0.020). The results of multivariate COX proportional risk regression analysis indicated that p-AKT/p-mTOR double-positive, higher LDH and IPI score 3-5 were independent prognostic factors for both OS and PFS, and the bulky tumor (>10 cm) for PFS of pediatric BL. Conclusion: The expression of p-AKT and p-mTOR may be a potential reference for diagnosis and the independent prognostic indicators of pediatric BL.

[HIV/AIDS related frailty syndrome in the elderly and related research progress].

Frailty syndrome, caused by degenerative changes in the body and the body vulnerability due to a variety of chronic diseases, is associated with adverse outcomes, such as fall, disability and mortality. With the development of antiretroviral therapy, the average life span of HIV/AIDS patients is extended, the number of elderly living with HIV/AIDS has increased, resulting the increase of the incidence of frailty syndrome in this population. The incidence of frailty syndrome in the elderly is associated with HIV infection and adverse reaction of antiretroviral therapy. Early assessment and intervention of frailty syndrome in elderly HIV/AIDS patients can reduce adverse clinical events and improve the quality of life.

[Role of a liver pathology standardized scoring system in the diagnosis of congenital biliary atresia and its relationship with prognosis].

Objective: To evaluate the diagnostic value of a histologic scoring system in congenital biliary atresia and its prognostic relevance. Methods: From January 2017 to June 2018 at Children's Hospital of Fudan University, 172 wedge liver biopsy specimens were obtained from infants with neonatal cholestasis [119 patients with congenital biliary atresia (CBA) and 53 patients with non-obstructive cholestasis as control]. A pathologist, single-blinded to the final diagnosis, made the histological diagnosis individually based on an 8-feature (portal ductal proliferation, bile duct reaction, bile plugs in portal ductules, liver fibrosis, edema in portal region, cholestasis, inflammatory cells infiltration in portal region, and ductal plate malformation), 21-point scoring system. Results: The main pathologic changes of biliary atresia were hepatocyte cholestasis, hyperplasia of bile ducts, fibrosis and infiltration of inflammatory cells in the portal area. There were significant difference in the degree of portal edema, bile duct hyperplasia and fibrosis between two groups (P<0.01). In addition, there were characteristic bile duct thrombosis in 97.5%(116/119) of the cases and abnormal development of bile duct plate in 9.2%(11/119) of the cases. Compared with non-CBA infant cholestasis group, the difference was statistically significant (P<0.05). The scoring system has high sensitivity, specificity (both 94.1%) and accuracy (94.3%) in the diagnosis of CBA. A score equal to or more than 11 points supported a diagnosis of CBA; whereas a score less than 11 points might suggest cholestasis. The degree of hepatic fibrosis and ductal plate malformation were related to prognosis. Conclusions: The liver pathology scoring system (8-feature, 21-point) is more accurate in diagnosing CBA than previous methods, which may guide the clinicopathological diagnosis. This histological scoring system also helps to assess the prognosis of CBA.

[Clinicopathological features and prognosis of pediatric alveolar rhabdomyosarcoma].

Objective: To investigate the clinicopathological features, diagnosis, differential diagnosis, treatment and prognosis of pediatric alveolar rhabdomyosarcoma (ARMS). Methods: The clinical and pathological data of 25 pediatric ARMS from 2008 to 2018 in Children's Hospital of Fudan University were collected. This histomorphology was assessed, and FOXO1 gene rearrangement was detected with FISH. The treatment details and outcome were analyzed. Results: There were 13 males and 12 females, with ages range from 19 days to 14 years (median 6 years, mean 6.2 years). The ARMS were located in the limbs (13 cases), head and neck (4 cases), trunk (3 cases), abdominal cavity (3 cases), scrotum (1 case) and perianal region (1 case). The ARMS were classified histologically as classic group (18 cases), solid group (5 cases) and embryonic-alveolar mixed group (2 cases). The typical pathological characteristics were small dark round cells arranged in solid, glandular and papillary patterns. The tumor cells expressed ALK (D5F3) (21/25, 84.0%), muscle origin DES (23/25, 92.0%), myogenin (22/25, 88.0%), MYOD1 (19/25, 76.0%), and in some cases they also expressed neurogenic marker Syn (6/25, 24.0%). FOXO1 gene rearrangement was detected by FISH in 24/25 cases (96.0%). Conclusion: Pediatric ARMS is rare and has unique clinicopathological characteristics, and needs to be differentiated from other common small round cell malignancies in children. ALK, DES, myogenin, MYOD1 immunohistochemistry and FOXO1 gene rearrangement are valuable aid in the diagnosis of ARMS.

Analysis of evolution and genetic diversity of sweetpotato and its related different polyploidy wild species I. trifida using RAD-seq.

BACKGROUND: Sweetpotato (Ipomoea batatas (L.) Lam.) is one of the most important crops from the family of Convolvulaceae. It is widely reported that cultivated sweetpotato was originated from Ipomoea trifida. However, diploid, tetraploid and hexaploid I. trifida were found in nature. The relationship, between them, and among them and sweetpotato, is remaining unclear. RESULTS: In the present study, we detected the genome diversity and relationship of sweetpotato and different polyploidy types I. trifida using Restriction-site Associated DNA Sequencing (RAD-seq). A total of 38,605 RAD-tags containing 832,204 SNPs had been identified. These tags were annotated using five public databases, about 11,519 tags were aligned to functional genes in various pathways. Based on SNP genotype, phylogenetic relation analysis results confirmed that cultivated sweetpotato has a closer relationship with I. trifida 6× than with I. trifida 4X and I. trifida 2×. Besides, 5042 SSRs were detected in I. trifida 6×, and 3202 pairs of high-quality SSR primers were developed. A total of 68 primers were randomly selected and synthesized, of which 61 were successfully amplified. CONCLUSION: These results provided new evidence that cultivated sweetpotato originated from I. trifida 6×, and that I. trifida 6× evolved from I. trifida 4X and I. trifida 2×. Therefore, using I. trifida 6× as the model plant of sweetpotato research should be more practical than using I. trifida 2× in the future. Meanwhile, sequence information and markers from the present study will be helpful for sweetpotato and I. trifida studies in the future.

Combination of all-stage and high-temperature adult-plant resistance QTL confers high-level, durable resistance to stripe rust in winter wheat cultivar Madsen.

KEY MESSAGE: Wheat cultivar Madsen has a new gene on the short arm of chromosome 1A and two QTL for all-stage resistance and three QTL for high-temperature adult-plant resistance that in combination confer high-level, durable resistance to stripe rust. Wheat cultivar Madsen has maintained a high-level resistance to stripe rust over 30 years. To map quantitative trait loci (QTL) underlying the high-level, durable resistance, 156 recombinant inbred lines (RILs) developed from cross Avocet S × Madsen were phenotyped with selected races of Puccinia striiformis f. sp. tritici in the greenhouse seedling tests, and in naturally infected fields during 2015-2017. The RILs were genotyped by SSR and SNP markers from genotyping by sequencing and the 90 K wheat SNP chip. Three QTL for all-stage resistance were mapped on chromosomes 1AS, 1BS and 2AS, and two QTL for high-temperature adult-plant (HTAP) resistance were mapped on 3BS and 6BS. The most effective QTL on 2AS, explaining 8.97-23.10% of the phenotypic variation in seedling tests and 8.60-71.23% in field tests, contained Yr17 for all-stage resistance and an additional gene for HTAP resistance. The 6BS QTL, detected in all field tests, was identified as Yr78. The 1AS QTL, conferring all-stage resistance, was identified as a new gene, which explained 20.45 and 30.23% of variation in resistance to races PSTv-37 and PSTv-40, respectively, and contributed significantly to field resistance at Pullman in 2015-2017, but was not detected at Mount Vernon. The interactions among QTL were mostly additive, and RILs with all five QTL had the highest level of resistance in the field, similar to Madsen. Genotyping 148 US Pacific Northwest wheat cultivars with markers for the 1AS, 2AS and 6BS QTL validated the genes and markers, and indicated their usefulness for marker-assisted selection.

[Poorly-differentiated chordoma with INI1 loss: a clinicopathologic study].

Objective: To analyze the clinicopathologic characteristics of poorly-differentiated chordoma with INI1 loss in children and to discuss the differential diagnosis. Methods: The clinical, radiological, histopathological profiles and molecular pathologic characteristics of two pediatric poorly differentiated chordoma cases with INI1 loss were reviewed. Results: The patients were a girl and a boy. Both lesions involved the slope. Both patients were presented with progressive muscle weakness or neck pain. Radiological examination showed clivus bone destruction and compression of the brain stem and cervical spinal cord. Histologically, the tumor cells lacked typical organization and were associated with inflammatory cells infiltration. On high power field, the tumor cells were ovoid or fusiform with prominent atypia, vacuolated nuclei and prominent nucleoli. By immunohistochemistry, the tumor cells expressed cytokeratin, epithelial membrane antigen, brachyury and were negative for INI1. In both cases, INI1 gene deletion was detected by FISH. Conclusions: Poorly-differentiated chordoma with INI1 loss mainly occurs in children. The morphology is different from classical chordoma.INI1 gene deletion is detectable by FISH. It can be distinguished from atypical teratoid/rhabdoid tumors and other neoplasms by the identification of nuclear brachyury expression. The loss of INI1 expression in poorly-differentiated chordoma might be associated with a poorly-differentiated morphology and an adverse prognosis.