Well-differentiated and dedifferentiated liposarcomas with prominent myxoid stroma: analysis of 56 cases

Histopathology. 2013 Jan;62(2):287-93. doi: 10.1111/j.1365-2559.2012.04348.x. Epub 2012 Sep 28.


Aims: Occasional cases of well-differentiated and dedifferentiated liposarcoma (LPS) contain myxoid stroma, leading to confusion with other sarcomas. The aim of this study was to analyse the clinicopathological and genetic features of well-differentiated/dedifferentiated LPS with prominent myxoid stroma.

Methods and results: Fifty-six cases of LPS (22 well-differentiated; 34 dedifferentiated) with prominent myxoid stroma were evaluated. Most arose in the retroperitoneum, abdominal cavity, or spermatic cord. The mean size was 170 mm. Myxoid LPS-like plexiform vessels were conspicuous in 11 cases of well-differentiated LPS. In 22 cases of dedifferentiated LPS, myxofibrosarcoma-like curvilinear vessels were prominent. In other cases, the myxoid component had variably bland or pleomorphic morphology. By immunohistochemistry, staining for MDM2 was positive in 95% of cases, and CDK4 in 78%. Cytogenetics in 13 cases showed ring and giant marker chromosomes. Fluorescence in-situ hybridization showed amplification of 12q13-15 in six cases evaluated. Of 30 patients with follow-up, all but one had local recurrences (up to four), but only one has so far had distant metastases.

Conclusions: Well-differentiated/dedifferentiated LPS with prominent myxoid stroma can closely resemble other sarcoma types, especially myxoid LPS and myxofibrosarcoma. The clinical presentation (large retroperitoneal or abdominal tumour) is a clue to the correct diagnosis; the degree of nuclear atypia helps to exclude myxoid LPS. Immunohistochemistry for MDM2 and CDK4 and genetic analysis can be useful to confirm the diagnosis.

MeSH terms

  • Abdominal Neoplasms / genetics
  • Abdominal Neoplasms / metabolism
  • Abdominal Neoplasms / pathology*
  • Adipocytes / metabolism
  • Adipocytes / pathology
  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Biomarkers, Tumor / metabolism
  • Chromosome Aberrations
  • Chromosomes, Human, Pair 12
  • Cyclin-Dependent Kinase 4 / metabolism
  • DNA, Neoplasm / analysis
  • Female
  • Gene Amplification
  • Humans
  • In Situ Hybridization, Fluorescence
  • Liposarcoma, Myxoid / genetics
  • Liposarcoma, Myxoid / metabolism
  • Liposarcoma, Myxoid / pathology*
  • Male
  • Middle Aged
  • Mucins / metabolism
  • Proto-Oncogene Proteins c-mdm2 / metabolism
  • Retroperitoneal Space
  • Soft Tissue Neoplasms / genetics
  • Soft Tissue Neoplasms / metabolism
  • Soft Tissue Neoplasms / pathology*
  • Stromal Cells / metabolism
  • Stromal Cells / pathology*
  • Young Adult


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