Objective To investigate the differential diagnostic features of subtypes of renal cell carcinoma(RCC) using dynamic contrast-enhanced MRI(DCE-MRI).Methods The MRI appearances of 77 RCCs, including 55 clear cell RCCs(CCRCC),14 papillary RCCs(PRCC) and 8 chromophobe RCCs(CRCC), were retrospectively analyzed and compared with findings of pathology. DCE-MRI was conducted in each case after intravenous administration of contrast agent. Region of interest measurements (cortical, nephrographic and delayed Phases) of signals within tumor and uninvolved renal cortex were used to calculate percentage signal intensity change and tumor-to-cortex enhancement index, and the data was analyzed by AVONA and t test. Results On unenhanced and enhanced MRI, most CRCCs showed homogeneous signal(7/8). CCRCC and PRCC often show inhomogenous signal with necrosis(36/55, 7/14). Hemorrhage and cystic degeneration were often found in PRCC (9/14). On the cortical, nephrographic and delayed phase images, CCRCCs showed greater signal intensity change[(296.15±60.27)%, (236.33±58.31)% and (216.83±46.72)%,respectively than PRCCs (79.70±18.84)%, (122.81±27.35)% and (117.55±20.63)%, respectively], and CRCCs showed intermediate change [(119.56±40.76)%, (163.06±33.91)% and (179.72±32.89)%, respectively].A phenomenon of quick staining and quick fainting was observed in CCRCCs. Both of CRCCs and PRCCs showed delayed enhancement. The tumor-to-cortex enhancement index at the cortical, nephrographic and delayed phases was highest for CCRCCs (1.26±0.34, 0.92±0.23 and 0.76±0.14, respectively), lowest for PRCCs (0.33±0.12, 0.41±0.23 and 0.35±0.11, respectively), and intermediate for CRCCs (0.54±0.10, 0.62±0.15 and 0.69±0.12, respectively,P＜0.01). The degree of enhancement was significantly different among the 3 subtypes at the every contrast enhanced phase (F=940.931, 124.515 and 38.194, P＜0.01), so was the tumor-to-cortex enhancement index(F=798.625,78.308 and 73.699, P＜0.01). There was a good consistency between MR appearances of the 3 RCC subtypes and pathological characteristics. Conclusion DCE-MRI could distinctly show imaging features of CCRCC, PRCC and CRCC, which were related to their pathological characteristics, and these features were helpful in predicting a specific subtype of RCC.

Objective:To explore the clinicopathological characteristics and prognosis of pancreatic gastrointestinal interstitial tumors(pGISTs).Methods:Three cases of pGISTs diagnosed in the Affiliated Tumor Hospital of Guangxi Medical University from August 2015 to October 2019 were analyzed retrospectively. Relevant literatures at home and abroad were searched and reviewed through PubMed, China knowledge Network, Wanfang and VIP databases. The sex, age, tumor size, tumor location, cystic or solid tumor, mode of treatment, mitosis, gene mutation, survival status and survival time were recorded, and the correlation between tumor cystic-solid characteristics and clinicopathological parameters was analyzed. Kaplan-Meier′s method was used to calculate the overall survival (OS) rate and disease-free survival (DFS) rate. Univariate and multivariate Cox regression models were used to analyze the independent risk factors affecting the prognosis of pGISTs.Results:In this group, 3 cases were combined with 71 cases reported in the literature, and a total of 74 cases of pGISTs were included. Among them, 36 cases were male and 38 were female, the age of onset was 55(19-84) years, and the diameter of the tumor was 8 cm(2-35 cm). The tumor location of 71 patients was recorded by literature; 30 cases (42.3%) were located in the head of the pancreas. The solid-cystic characteristics of tumor in 63 patients were recorded by literature, and 33 cases (52.4%) were solid. The mode of treatment of 74 patients was recorded, and 60 cases (81.1%) underwent radical resection. The mitosis figures of 59 patients were recorded, and 33 cases (55.9%) were <5/50 high power field of vision (HPF). The gene mutation of 14 patients was recorded, and 11 cases (78.6%) were c-kit exon gene mutation. Correlation analysis showed that the cystic-solid characteristics of the tumor were significantly correlated with tumor location, tumor diameter and mitosis figures, but not with age, sex, histological type, Ki-67 index and modification National Institutes of Health(mNIH) classification. The 5-year OS rate of 51 patients after radical resection was 88.8%, and the 5-year DFS rate was 60.3%. The 1-year OS rate of patients receiving palliative treatment was 51.9%, and the 1-year fatality rate was 33.3%. Univariate Cox regression analysis showed that male ( P=0.083), mitosis figures >5/50 HPF ( P=0.008)and CD 34 negative ( P=0.055)were risk factors for postoperative recurrence of pGISTs, while multivariate Cox regression analysis showed that mitosis figures >5/50 HPF ( P=0.023)was an independent risk factor for the prognosis of pGISTs. Kaplan-Meier survival analysis showed that patients with mitosis figures ≤5/50 HPF had a higher survival rate ( P=0.0003), but there was no significant difference on prognosis between patients with 10/50 HPF and >10/50 HPF( P=0.3075). Conclusions:pGISTs usually occured in the head of pancreas, and the tumor volume was usually found to be large. The main treatment was radical operation, and the main mutation type was exon mutation of c-kit gene. Nuclear fission image figures >5/50HPF was an independent risk factor for postoperative recurrence.