title: Urothelial carcinoma of the upper urinary tract: inverted growth pattern is predictive of microsatellite instability.
abstract: Urothelial carcinoma of the renal pelvis and ureter may develop as a manifestation of hereditary nonpolyposis colorectal cancer syndrome (HNPCC), a disorder characterized by mutation or inactivation of a number of DNA mismatch repair genes and detectable as microsatellite instability (MSI). Some urothelial carcinomas display areas of endophytic, or inverted, growth. In this study, urothelial cancers of the upper urinary tract (n = 132) from patients treated at 2 tertiary care centers were studied to identify an association between growth pattern and MSI. Thirty-five neoplasms were microsatellite unstable (26.5%), and MSI was more frequent in papillary lesions than in sessile urothelial cancers (P = .033). The amount of inverted growth was estimated as a percentage of the total tumor. The interobserver and intraobserver concordance in recognizing inverted growth was good, and 65.7% of microsatellite-unstable tumors exhibited at least 20% of an inverted growth component, compared with only 17.5% of microsatellite-stable tumors (P < .0001). In this series, inverted growth predicted MSI with a sensitivity and specificity of .82. Inverted growth in urothelial carcinomas of the upper urinary tract may serve as a marker lesion for MSI and may help identify patients who should be offered testing for HNPCC.
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic and Foundation, Rochester, MN, USA.
authors.forename: Arndt
authors.initials: A
authors.lastname: Hartmann
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Dietmaier
authors.forename: Ferdinand
authors.initials: F
authors.lastname: Hofstädter
authors.forename: Lawrence J
authors.initials: LJ
authors.lastname: Burgart
authors.forename: John C
authors.initials: JC
authors.lastname: Cheville
authors.forename: Hagen
authors.initials: H
authors.lastname: Blaszyk
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002295:Carcinoma, Transitional Cell / Q000235:genetics* / Q000473:pathology*; D002455:Cell Division; D005260:Female; D006801:Humans; D007682:Kidney Pelvis / Q000473:pathology; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics*; D008875:Middle Aged; D015588:Observer Variation; D012680:Sensitivity and Specificity; D014516:Ureteral Neoplasms / Q000235:genetics / Q000473:pathology; D014571:Urologic Neoplasms / Q000235:genetics* / Q000473:pathology*