Undifferentiated high-grade pleomorphic sarcoma of the common bile duct: A case report and review of literature.

BACKGROUND: Undifferentiated pleomorphic sarcoma (UPS) is a rare malignant mesenchymal tumor with a poor prognosis. It mainly occurs in the extremities, trunk, head and neck, and retroperitoneum regions. Owing to the lack of specific clinical manifestations and imaging features, UPS diagnosis mainly depends on pathological and immunohistochemical examinations for exclusive diagnosis. Here we report an extremely rare case of high-grade UPS in the common bile duct (CBD). There are limited available data on such cases. CASE SUMMARY: A 70-year-old woman was admitted to our department with yellow eyes and urine accompanied by upper abdominal distending pain for 2 wk. Her laboratory data suggested significantly elevated hepatorenal function levels. The imaging data revealed calculous cholecystitis, intrahepatic and extrahepatic bile duct dilation with extrahepatic bile duct calculi, and a space-occupying lesion at the distal CBD. After endoscopic biliary stenting and symptomatic support therapy, CBD exploration and biopsy were performed. The frozen section indicated malignant spindle cell tumor of the CBD mass, and further radical pancreaticoduodenectomy was performed. Finally, the neoplasm was diagnosed as a high-grade UPS combined with the light-microscopic morphology and immunohistochemical results. CONCLUSION: This extremely rare case highlighted the need for increasing physicians' vigilance, reducing the odds of misdiagnosis, and providing appropriate treatment strategies.

Anastomosing hemangioma arising from the left renal vein: A case report.

BACKGROUND: Anastomosing hemangioma (AH) is a rare subtype of benign hemangioma that is most commonly found in the genitourinary tract. Due to the lack of specific clinical and radiologic manifestations, it is easily misdiagnosed preoperatively. Here, we report a case of AH arising from the left renal vein that was discovered incidentally and confirmed pathologically, and then describe its imaging characteristics from a radiologic point of view and review its clinicopathologic features and treatment. CASE SUMMARY: A 74-year-old woman was admitted to our department for a left retroperitoneal neoplasm measuring 2.6 cm × 2.0 cm. Her laboratory data showed no significant abnormalities. A non-contrast-enhanced computed tomography (CT) scan showed a heterogeneous density in the neoplasm. Non-contrast-enhanced magnetic resonance imaging (MRI) revealed a heterogeneous hypointensity on T1-weighed images and a heterogeneous hyperintensity on T2-weighed images. On contrast-enhanced CT and MRI scans, the neoplasm presented marked septal enhancement in the arterial phase and persistent enhancement in the portal phase, and its boundary with the left renal vein was ill-defined. Based on these clinical and radiological manifestations, the neoplasm was initially considered to be a neurogenic neoplasm in the left retroperitoneum. Finally, the neoplasm was completely resected and pathologically diagnosed as AH. CONCLUSION: AH is an uncommon benign hemangioma. Preoperative misdiagnoses are common not only because of a lack of specific clinical and radiologic manifestations but also because clinicians lack vigilance and diagnostic experience in identifying AH. AH is not exclusive to the urogenital parenchyma. We report the first case of this neoplasm in the left renal vein. Recognition of this entity in the left renal vein can be helpful in its diagnosis and distinction from other neoplasms.

Radiological aspects of giant hepatocellular adenoma of the left liver: A case report.

BACKGROUND: Hepatocellular adenoma (HCA) is very rare and has a high misdiagnosis rate through clinical and imaging examinations. We report a case of giant HCA of the left liver in a young woman that was diagnosed by medical imaging and pathology. CASE SUMMARY: A 21-year-old woman was admitted to our department for a giant hepatic tumor measuring 22 cm × 20 cm × 10 cm that completely replaced the left hepatic lobe. Her laboratory data only suggested mildly elevated liver function parameters and C-reactive protein levels. A computed tomography (CT) scan showed mixed density in the tumor. Magnetic resonance imaging (MRI) of the tumor revealed a heterogeneous hypointensity on T1-weighed MR images and heterogeneous hyperintensity on T2-weighed MR images. On dynamic contrast CT and MRI scans, the tumor presented marked enhancement and the subcapsular feeding arteries were clearly visible in the arterial phase, with persistent enhancement in the portal and delayed phases. Moreover, the tumor capsule was especially prominent on T1-weighted MR images and showed marked enhancement in the delayed phase. Based on these imaging manifestations, the tumor was initially considered to be an HCA. Subsequently, the tumor was completely resected and pathologically diagnosed as an HCA. CONCLUSION: HCA is an extremely rare hepatic tumor. Preoperative misdiagnoses were common not only due to the absence of special clinical manifestations and laboratory examination findings, but also due to the clinicians' lack of practical diagnostic experience and vigilance in identifying HCA on medical images. Our case highlights the importance of the combination of contrast-enhanced CT and MRI in the preoperative diagnosis of HCA.

Development of a core snubber for the neutral beam injector on EAST.

A 4-MW ion source was developed for the neutral beam injector (NBI) on Experimental Advanced Superconducting Tokamak (EAST). Breakdown nevertheless can happen during ion source conditioning and routine operations and is deleterious to the high-power ion source. To protect this ion source, a core snubber was designed to absorb the breakdown energy of the EAST-NBI ion source. A prototype core snubber was developed and tested using the ion-source test bed. The results show that with a core snubber, short-circuit currents at different high-power voltages were about one-tenth of the current without the snubber. The residual energy of the distributed capacitors had been absorbed successfully and the core snubber does protect the source from damage during breakdown. The results verified the successful development of a core snubber for the EAST-NBI.

Investigation of the adhesive bonding technology for the insulator structure of EAST neutral beam injector.

A key issue on the development of EAST ion source was the junction design of insulator structure, which consists of three insulators and four supporting flanges of electrode grid. Because the ion source is installed on the vertical plane, the insulator structure has to withstand large bending and shear stress due to the gravity of whole ion source. Through a mechanical analysis, it was calculated that the maximum bending normal stress was 0.34 MPa and shear stress was 0.23 MPa on the insulator structure. Due to the advantages of simplicity and high strength, the adhesive bonding technology was applied to the junction of insulator structure. A tensile testing campaign of different junction designs between insulator and supporting flange was performed, and a junction design of stainless steel and fiber enhanced epoxy resin with epoxy adhesive was determined. The insulator structure based on the determined design can satisfy both the requirements of high-voltage holding and mechanical strength.