Nonurothelial benign tumors

Author: Monika Roychowdhury, M.D. (see Authors page)

Revised: 8 June 2016, last major update December 2014

Copyright: (c) 2003-2016,, Inc.

PubMed Search: Bladder [title] neurofibroma
Cite this page: Neurofibroma. website. Accessed December 11th, 2018.
Definition / general
  • Benign mesenchymal tumor with nerve sheath differentiation
  • Similar to counterparts elsewhere
  • Uncommon
  • Classically occurs in young patients with a slight male predominance
  • Presents early in life
  • Strongly associated with neurofibromatosis type 1 (Cancer 1999;86:505, PDF)
Clinical features
  • Plexiform neurofibromas are associated with neurofibromatosis; diffuse neurofibromas are not (Am J Surg Pathol 2008;32:907)
  • May present with hematuria, irritative voiding symptoms and symptoms related to pelvic mass effect
Case reports
Gross description
  • Polypoid or diffuse
Gross images

Images hosted on other servers:
Missing Image

Plexiform neurofibroma: M - mucosa is
surrounded by masses of nodules

Microscopic (histologic) description
  • Histology is same as neurofibromas elsewhere
  • Hypocellular proliferation of spindle cells with wavy bland nuclei
  • Cells are arranged in loose fascicles intermixed with bundles of collagen
Microscopic (histologic) images

Images hosted on other servers:

Lamina propria shows meissner-type corpuscles

Bland spindled cells in fibrous stroma

Plexiform neurofibroma

Positive stains
Negative stains
Differential diagnosis
  • Leiomyoma: has cigar-shaped nuclei, S100 negative, positive for smooth muscle actin and desmin
  • Inflammatory myofibroblastic tumor: reactive spindle cells in inflammatory background
  • Malignant peripheral nerve sheath tumor: has marked atypia and increased mitotic activity, may have necrosis