Kidney tumor - cysts, children, adult benign
Childhood neoplasms
Metanephric stromal tumor

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

Revised: 13 January 2017, last major update December 2011

Copyright: (c) 2003-2017,, Inc.

PubMed Search: "Metanephric stromal tumor" kidney

Cite this page: Metanephric stromal tumor. website. Accessed February 25th, 2018.
Definition / general
  • Benign spindle cell neoplasm of pediatric kidney composed of bland spindled cells that entrap native kidney
  • Similar to and often misdiagnosed as mesoblastic nephroma
  • May be related to Wilms tumor (Clin Lab Med 2005;25:379)
  • Excision is curative
Gross description
  • Fibrous lesion centered in renal medulla containing smooth walled cysts; mean 5.5 cm
Microscopic (histologic) description
  • Nodular low power appearance
  • Identical to stromal component of metanephric adenofibroma
  • Bland spindle cells with thin, tapered and hyperchromatic nuclei and indistinct cytoplasm (may have epithelioid areas) that entrap native kidney, usually undermine calyceal or pelvic urothelium and may entrap nerves
  • Nonencapsulated with a scalloped border with renal cortex
  • Hypo and hypercellular areas with onion skin cuffing around entrapped renal tubules
  • Stroma may show glial, cartilaginous or neuroblastic differentiation
  • Angiodysplasia of entrapped arterioles
  • May show juxtaglomerular cell hyperplasia in entrapped glomeruli
  • No vascular invasion, no mitotic figures
Virtual slides

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Metanephric stromal tumor

Positive stains
Negative stains
Differential diagnosis