title: Long-term outcome of primary Papillary Urothelial Neoplasm of Low Malignant Potential (PUNLMP) including PUNLMP with inverted growth.
abstract: BACKGROUND
  Few larger studies have evaluated the long-term outcome after a diagnosis of papillary urothelial neoplasm of low malignant potential (PUNLMP), demonstrating a broad range of recurrence and progression rates. Additionally, no study has addressed the outcome of PUNLMP exhibiting inverted growth. We evaluated the long term clinical outcome of primary papillary urothelial neoplasm of low malignant potential (PUNLMP), including PUNLMP with inverted growth in a large single center study.
  
  
  METHODS
  We evaluated 189 primary PUNLMP (177 exophytic, 12 inverted), diagnosed from January 1, 2000 to December 31, 2009, in a centralized uropathology practice. We excluded PUNLMP diagnosed after a previous or with a concurrent urothelial neoplasm. Recurrence was defined as any subsequent urothelial neoplasm, regardless of the grade. Progression was defined as any subsequent higher-grade or invasive urothelial neoplasm. Recurrence and progression were established only if documented on a subsequent biopsy. Descriptive statistical analysis was performed using Microsof Excel software package.
  
  
  RESULTS
  The location of PUNLMP included bladder (187) and renal pelvis and ureter (1 each). After a median follow-up of 61 months (range, 9-128 months), 20.1% patients developed a recurrence. Recurrence with PUNLMP only was found in 9% of patients. Subsequent low-grade urothelial carcinoma was documented in 9.5% of patients. Progression to high-grade urothelial carcinoma was found in 1.6% patients (1% with muscle invasion). No patients with recurrent PUNLMP or subsequent low-grade carcinoma demonstrated invasion. All patients with PUNLMP exhibiting an inverted growth had no recurrence or progression on follow-up.
  
  
  CONCLUSIONS
  In this study, primary PUNLMP recurred primarily either as PUNLMP or low grade urothelial carcinoma. Primary PUNLMP rarely progressed to high grade or invasive carcinoma on long term follow-up. No recurrence or progression was documented on follow-up for PUNLMP that demonstrated exclusively inverted growth.
  The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1332825572154074.
authors.affiliation: Department of Pathology and Laboratory Medicine, Calgary Laboratory Service and University of Calgary, Rockyview General Hospital, 7007 14 Street, Calgary, AB, Canada. jay.maxwell@medportal.ca.
authors.forename: Jay P
authors.initials: JP
authors.lastname: Maxwell
authors.affiliation: Department of Pathology and Laboratory Medicine, Calgary Laboratory Service and University of Calgary, Rockyview General Hospital, 7007 14 Street, Calgary, AB, Canada. Cheng.Wang@cdha.nshealth.ca.
authors.forename: Cheng
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Pathology and Laboratory Medicine, Calgary Laboratory Service and University of Calgary, Rockyview General Hospital, 7007 14 Street, Calgary, AB, Canada. Nicholas.wiebe@cls.ab.ca.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Wiebe
authors.affiliation: Department of Pathology and Laboratory Medicine, Calgary Laboratory Service and University of Calgary, Rockyview General Hospital, 7007 14 Street, Calgary, AB, Canada. Asli.yilmaz@cls.ab.ca.
authors.forename: Asli
authors.initials: A
authors.lastname: Yilmaz
authors.affiliation: Department of Pathology and Laboratory Medicine, Calgary Laboratory Service and University of Calgary, Rockyview General Hospital, 7007 14 Street, Calgary, AB, Canada. kiril.trpkov@cls.ab.ca.
authors.forename: Kiril
authors.initials: K
authors.lastname: Trpkov
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000416:Alberta; D001706:Biopsy; D002277:Carcinoma / Q000473:pathology* / Q000628:therapy; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local; D018308:Papilloma, Inverted / Q000473:pathology* / Q000628:therapy; D013997:Time Factors; D016896:Treatment Outcome; D014516:Ureteral Neoplasms / Q000473:pathology* / Q000628:therapy; D001749:Urinary Bladder Neoplasms / Q000473:pathology* / Q000628:therapy; D019459:Urothelium / Q000473:pathology*; D055815:Young Adult