Palisaded myofibroblastoma of the breast: a tumor closely mimicking schwannoma: Report of 2 cases

Hum Pathol. 2013 Sep;44(9):1941-6. doi: 10.1016/j.humpath.2013.01.018. Epub 2013 Apr 8.


Myofibroblastoma is a relatively rare, benign mesenchymal tumor that typically occurs in the breast parenchyma. Unlike mammary-type myofibroblastoma, myofibroblastoma that primarily arises in the lymph nodes exhibits nuclear palisading, and the term palisaded myofibroblastoma has been proposed, accordingly. We report 2 unusual cases of myofibroblastoma of the male breast, which showed a predominant (>90% of the entire tumor) nuclear palisading and Verocay-like bodies. The present cases represent a hitherto unreported variant of mammary-type myofibroblastoma closely mimicking schwannoma. The diagnosis of myofibroblastoma was supported by immunohistochemical analyses showing a diffuse staining for desmin and CD34. In addition, the diagnosis of myofibroblastoma was confirmed in 1 case cytogenetically by the demonstration of the monoallelic loss of the FOXO1/13q14 locus by fluorescence in situ hybridization. Pathologists should be aware of this unusual variant of mammary myofibroblastoma to assure a correct diagnosis.

Keywords: Breast; Fluorescence in situ hybridization; Immunohistochemistry; Myofibroblastoma; Schwannoma.

Publication types

  • Case Reports

MeSH terms

  • Aged
  • Antigens, CD34 / metabolism
  • Biomarkers, Tumor / genetics
  • Biomarkers, Tumor / metabolism
  • Breast Neoplasms, Male / genetics
  • Breast Neoplasms, Male / metabolism
  • Breast Neoplasms, Male / pathology*
  • Cell Nucleus / pathology
  • DNA, Neoplasm / analysis
  • Desmin / metabolism
  • Diagnosis, Differential
  • Forkhead Box Protein O1
  • Forkhead Transcription Factors / genetics
  • Forkhead Transcription Factors / metabolism
  • Humans
  • In Situ Hybridization, Fluorescence
  • Male
  • Mastectomy, Segmental
  • Middle Aged
  • Neoplasms, Muscle Tissue / genetics
  • Neoplasms, Muscle Tissue / metabolism
  • Neoplasms, Muscle Tissue / pathology*
  • Neurilemmoma / diagnosis*
  • Treatment Outcome


  • Antigens, CD34
  • Biomarkers, Tumor
  • DNA, Neoplasm
  • Desmin
  • FOXO1 protein, human
  • Forkhead Box Protein O1
  • Forkhead Transcription Factors