Soft Tissues: Liposarcoma / malignant lipomatous tumors

2000-05-01   Nils Mandahl 

1.Department of Clinical Genetics, University Hospital, Lund, Sweden

Summary

Note

liposarcomas are adipose tissue tumors, including low-malignant to highly malignant subtypes, constituting 10-15% of soft tissue sarcomas

Classification

Classification

  • Well-differentiated liposarcoma: the well-differentiated liposarcomas are tumors of low grade malignancy that may recur locally but not metastasize; the terminolgy of subtypes is not straightforward; three related sybtypes have been distinguished: lipoma-like (the most common form), inflammatory, and sclerosing; other terms that have been suggested to describe at least subsets of these tumors are atypical lipoma and atypical lipomatous tumor
  • Myxoid liposarcoma / round cell liposarcoma: myxoid liposarcoma is the most common form of liposarcomas, constituting about half of the cases, with a relatively favorable prognosis; the much less common, and more aggressive round cell liposarcoma is regarded as a poorly differentiated variant of myxoid liposarcoma; pure round cell liposarcomas are very rare, and more often the tumors represent mixed liposarcomas with both myxoid and round cell components at different proportions; in recurrences the round cell component may increase
  • Pleomorphic liposarcoma: the pleomorphic liposarcomas are highly malignant tumors showing a disorderly growth pattern and extensive cellular pleomorphism

    • Clinics and Pathology

    Epidemiology

    the reported annual incidence of liposarcoma is in the range of 2.5 per million; liposarcomas are tumors of adult life with a median age of 55-60 years; patients younger than 15 years are rare; men are slightly more often affected than women

    Clinics

    the major sites are the lower extremities and the retroperitoneum; most tumors range from 5 to 10 cm in diameter, but much larger tumors are not rarely seen.

    Evolution

    the risk of distant metastases relate to the type and degree of histological differentiation; well-differentiated liposarcomas may occasionally dedifferentiate to highly malignant tumors that may metastasize

    Prognosis

    the survival rates are primarily dependent on the histological type, and patients with well-differentiated and myxoid liposarcomas, on the one hand, fare much better than round cell and pleomorphic liposarcomas on the other hand

    Cytogenetics

    Cytogenetics morphological

    Pleomorphic liposarcoma
    few cases have been cytogenetically characterized; they invariably show complex karyotypic changes, with no characteristic changes identified, and an extensive intratumor heterogeneity

    Bibliography

    Pubmed IDLast YearTitleAuthors

    Citation

    Nils Mandahl

    Soft Tissues: Liposarcoma / malignant lipomatous tumors

    Atlas Genet Cytogenet Oncol Haematol. 2000-05-01

    Online version: http://atlasgeneticsoncology.org/solid-tumor/5029/gene-fusions-explorer/