title: Primary Carcinoid Tumor of the Renal Pelvis Arising From Intestinal Metaplasia: An Unusual Histogenetic Pathway?
abstract: Primary carcinoid tumor of the renal pelvis is a rare neoplasm with few cases reported in the literature. Here we present the clinical and histopathologic findings of a primary carcinoid tumor arising in the left renal pelvis of a horseshoe kidney in a 61-year-old female patient.
  
  
  
  Pathologic features were evaluated with standard hematoxylin and eosin sections and immunohistochemical studies. A literature review was performed to place our case in context to previous reports.
  
  
  
  The tumor was associated with intestinal metaplasia with high-grade dysplasia and neuroendocrine hyperplasia. Molecular testing for microsatellite instability and loss of heterozygosity were negative.
  
  
  
  This report portrays a unique presentation of carcinoid tumor arising from intestinal metaplasia of the pelvic urothelium, and supports its histogenesis from urothelial intestinal metaplasia and neuroendocrine hyperplasia.
authors.affiliation: *Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN †Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE.
authors.forename: Maria G
authors.initials: MG
authors.lastname: Kuba
authors.forename: Allison
authors.initials: A
authors.lastname: Wasserman
authors.forename: Cindy L
authors.initials: CL
authors.lastname: Vnencak-Jones
authors.forename: Julia A
authors.initials: JA
authors.lastname: Bridge
authors.forename: Lan
authors.initials: L
authors.lastname: Gellert
authors.forename: Omar
authors.initials: O
authors.lastname: Hameed
authors.forename: Giovanna A
authors.initials: GA
authors.lastname: Giannico
mesh_terms: D002276:Carcinoid Tumor / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000378:metabolism / Q000473:pathology; D007682:Kidney Pelvis / Q000378:metabolism / Q000473:pathology; D008679:Metaplasia; D008875:Middle Aged