Three-Year Experience of an External ProficiencyTesting Survey for Next-Generation Sequencing-Based Testing for Germline Mutation

Background@#Next-generation sequencing is a powerful technology thatallows simultaneous analysis of several genes but also demands a welldesignedquality management system owing to its complexity. We aimed toanalyze the results of next-generation sequencing (NGS)-germline proficiencytesting (PT) survey performed by the Korean Association of External QualityAssessment Service during 2017–2019 to assess the current status of theNGS-based genetic testing in Korea. @*Methods@#The recent 3-year results from the PT survey were investigated.During this period, PT survey was performed twice every year with two orthree challenges per round. Correct results (%) were calculated from alltested regions; the trend by year and variation type was analyzed and theprobable causes estimated. @*Results@#During this period, the number of participating laboratoriesincreased from 5 to 22. The correct results were 97.2% in average andshowed a gradual increase with year. The most common ‘unacceptable’results were false-negative or false-positive, followed by inappropriatenomenclature and zygosity assignment. @*Conclusions@#The PT survey shows that the overall performance of NGSlaboratories in Korea is highly confident, although some improvements maybe needed. A method-based PT survey for the NGS test serves as a usefulapproach to assess the performance of NGS laboratories.

Angiomyolipoma of the Perinephric Space: Case Report

Angiomyolipomas commonly originate from renal parenchyma but extremely rarely from perinephric space. We report a case of angiomyolipoma of the perinephric space confirmed by radical nephrectomy. A 13-year-old boy presented with left flank pain and abdominal distension, first experienced five months earlier. Ultrasonography and CT indicated that in the space surrounding the left kidney, a huge fat-containing mass with linear strands was present.

Spontaneous Rupture of Choledochal Cyst: Case Report

Spontaneous rupture of a choledochal cyst leading to biliary peritonitis is a rare complication which can be fatal if not promptly diagnosed. The authors report the ultrasound and CT findings of two cases of spontaneous choledochal cystic rupture and the biliary peritonitis which ensued.