Kidney tumor - cysts, children, adult benign
Benign (usually) adult tumors
Solitary fibrous tumor

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

Revised: 30 January 2017, last major update March 2012

Copyright: (c) 2003-2012, PathologyOutlines.com, Inc.

PubMed Search: "Solitary fibrous tumor" kidney

Cite this page: Solitary fibrous tumor. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/kidneytumorsolitary.html. Accessed May 27th, 2017.
Definition / general
  • Benign (90%) tumor of patternless or storiform spindle cells with bland nuclear features, mixed with dense collagen
  • See also Soft tissue tumor chapter
Epidemiology
  • Rare in kidney, arises from serosal surfaces of pleura and other sites
Clinical features
Case reports
Treatment
  • Excision
  • Almost always benign behavior
Gross description
  • Large (up to 14 cm, Am J Surg Pathol 2001;25:1194), well circumscribed
  • Slightly nodular, grayish tan firm cut surface with hemorrhage / cystic change
Gross images

Images hosted on other servers:

Various images

Malignant tumor

Microscopic (histologic) description
  • Patternless, hemangiopericytomatous or storiform pattern of bland spindle cells mixed with dense collagenous bands that may entrap renal tubules
  • Variable lymphoplasmacytic infiltrate, variable myxoid change
  • Usually no necrosis, no cystic change and no mitotic figures
Microscopic (histologic) images

Images hosted on other servers:

Patternless pattern of bland spindle cells

Various images malignant tumor

Entrapped renal tubules


Malignant tumor with atypia and mitotic figures

Left: CD34+, right: vimentin

Top to bottom: CD34+, CD99+, Ki67

Positive stains
Negative stains
Electron microscopy description
  • Fibroblast-like cells (irregular nuclei, prominent Golgi, branching rough endoplasmic reticulum, variable mitochondria and intermediate filaments, no thin filaments with focal densities, no tonofilaments and no cell-cell junctions)
  • No myoepithelial or epithelial differentiation
Differential diagnosis