Kidney tumor - cysts, children, adult benign
Benign (usually) adult tumors
Fibroepithelioid polyp of renal pelvis

Author: Mandolin Ziadie, M.D. (see Authors page)

Revised: 17 January 2017, last major update January 2012

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PubMed Search: Fibroepithelioid polyp [title] AND renal pelvis

Cite this page: Fibroepithelioid polyp of renal pelvis. PathologyOutlines.com website. http://pathologyoutlines.com/topic/kidneytumorfibroepithelialpolyp.html. Accessed June 23rd, 2017.
Definition / general
  • Mesodermal tumor that is more commonly diagnosed in the ureter
Epidemiology
  • Rare (< 50 cases reported)
Clinical features
  • Presents in young adults (usually women) with gross and painless hematuria
  • Xray: polypoid filling defect on intravenous pyelogram
Radiology images

Images hosted on other servers:

Polypoid filling defect on intravenous pyelogram

Case reports
Treatment
  • Benign; local resection if causes obstruction
Gross description
  • Polypoid exophytic mass with smooth glistening external surface and gray / white / pink cut surface
Gross images

Images hosted on other servers:

Large polyp almost completely fills renal pelvis

Microscopic (histologic) description
  • Thick fibrous stalk and connective tissue core covered by urothelium
  • Connective tissue core contains collagen, smooth muscle and blood vessels with edema and inflammatory cells
Microscopic (histologic) images

Images hosted on other servers:

Urothelium covers
fibrovascular tissue
with loose stroma and
small blood vessels

Negative stains
Differential diagnosis
  • Hemangioma: vascular lesion, no fibrous stalks and no urothelial cells
  • Leiomyoma: smooth muscle cells, no fibrovascular stalks and no urothelium
  • Schwannoma: neural features, no smooth muscle cells, no fibrovascular stalks and no urothelium; S100+