Heterologous Liposarcomatous Differentiation in Malignant Phyllodes Tumor is Histologically Similar but Immunohistochemically and Molecularly Distinct from Well-differentiated Liposarcoma of Soft Tissue

Breast J. 2016 May;22(3):282-6. doi: 10.1111/tbj.12567. Epub 2016 Feb 4.

Abstract

Malignant phyllodes tumor (PT) infrequently displays heterologous differentiation, and when present is most often liposarcomatous. We identified five cases of malignant PT with regions identical to well-differentiated liposarcoma (WDLS) of soft tissue and evaluated them for MDM2 and CDK4 gene expression and amplification using immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), respectively. Despite indistinguishable morphology all cases of malignant PT with WDLS-like liposarcomatous differentiation were negative for MDM2 and CDK4 IHC and FISH, supporting different underlying pathogenesis.

Keywords: CDK4; MDM2; liposarcoma; phyllodes tumor.

MeSH terms

  • Adult
  • Biomarkers, Tumor / genetics
  • Biomarkers, Tumor / metabolism
  • Breast Neoplasms / genetics
  • Breast Neoplasms / metabolism
  • Breast Neoplasms / pathology*
  • Cyclin-Dependent Kinase 4 / genetics
  • Cyclin-Dependent Kinase 4 / metabolism
  • Female
  • Humans
  • Immunohistochemistry
  • In Situ Hybridization, Fluorescence
  • Liposarcoma / genetics
  • Liposarcoma / metabolism
  • Liposarcoma / pathology*
  • Middle Aged
  • Phyllodes Tumor / genetics
  • Phyllodes Tumor / metabolism
  • Phyllodes Tumor / pathology*
  • Proto-Oncogene Proteins c-mdm2 / genetics
  • Proto-Oncogene Proteins c-mdm2 / metabolism
  • Soft Tissue Neoplasms / genetics
  • Soft Tissue Neoplasms / metabolism
  • Soft Tissue Neoplasms / pathology

Substances

  • Biomarkers, Tumor
  • MDM2 protein, human
  • Proto-Oncogene Proteins c-mdm2
  • CDK4 protein, human
  • Cyclin-Dependent Kinase 4