Vulva, vagina & female urethra
Mammary type myofibroblastoma

Topic Completed: 1 August 2016

Minor changes: 3 November 2020

Copyright: 2003-2021,, Inc.

PubMed Search: Mammary type myofibroblastoma vulva

Carlos Parra-Herran, M.D.
Page views in 2020: 763
Page views in 2021 to date: 23
Cite this page: Parra-Herran C. Mammary type myofibroblastoma. website. Accessed January 24th, 2021.
Definition / general
  • Initially described in the breast, myofibroblastoma occurs in a wide range of anatomic locations
  • It rarely involves the lower genital tract, predominantly vagina (less commonly vulva and cervix)
  • History of exogenous hormone or tamoxifen exposure has been documented in some cases
Clinical features
  • Age of presentation ranges from 23 to 80 years
  • Most patients complain of a mass
Prognostic factors
  • Benign behavior with no recurrences or death after conservative excision
  • Local excision is curative
Gross description
  • Well circumscribed mass, sometimes polypoid
  • Rubbery and whorled cut surface
Microscopic (histologic) description
  • Tumor is well demarcated, without a capsule, and with a sharp interface with the overlying dermis
  • Tumor contains haphazardly oriented fascicles of bland spindle cells
  • Interspersed matrix is composed of hyalinized collagen bundles
  • A variable adipose tissue component is commonly seen
Positive stains
Negative stains
Molecular / cytogenetics description
  • Monoallelic loss of FOXO1 / FOX1A1 on 13q14 has been demonstrated in mammary and vulvovaginal myofibroblastoma (Hum Pathol 2012;43:1887)
Differential diagnosis
  • Cellular angiofibroma: morphologic overlap and similar genetic findings (both have loss of FOX1A1 at 13q14), but cellular angiofibroma has a more prominent vascular component and lacks thick hyalinized collagen bundles
  • Angiomyofibroblastoma: areas of hypo- and hypercellularity, more prominent vascular component (delicate capillary-sized vessels), CD34 negative
  • Aggressive angiomyxoma: prominent myxoid change with hypocellularity; lacks intersecting fascicles and thick hyalinized collagen bundles
  • Metastatic adenocarcinoma from gastrointestinal tract origin: signet ring cells
Back to top
Image 01 Image 02