Pleomorphic Liposarcoma

Pleomorphic Liposarcoma

Thomas Mentzel, MD

Gross photograph shows an intramuscular, partly necrotic neoplasm with gray-white indurated cut surfaces.

Hematoxylin & eosin shows a high-grade pleomorphic sarcoma containing numerous atypical multinucleated giant cells associated with pleomorphic lipoblasts image.



  • Pleomorphic liposarcoma (PLS)


  • Pleomorphic high-grade sarcoma containing variable amounts of pleomorphic lipoblasts

  • No areas of atypical lipomatous tumor are present

  • No sarcomatous component of a different line of differentiation is present



  • Incidence

    • Rarest subtype of liposarcoma

    • Accounts for approximately 5% of all liposarcomas

    • Accounts for approximately 20% of all pleomorphic sarcomas

  • Age

    • Most cases arise in elderly patients (> 50 years old)

  • Gender

    • Equal sex distribution


  • Most cases arise in extremities (lower > upper)

  • Trunk and retroperitoneum are more rarely involved

  • Rare sites include mediastinum, paratesticular region, scalp, abdominal/pelvic cavities

  • Most cases arise in deep soft tissues

  • Subcutaneous cases are rare

  • Purely dermal cases are very rare but may occur


  • Deep mass

  • Painless mass

  • Firm enlarging mass

Natural History

  • Many patients have short preoperative history

  • Clinically aggressive neoplasm

  • 30-50% metastasis rate

  • Lung represents preferred site of metastases

  • 40-50% overall tumor-associated mortality

  • 5-year survival rate of 60-65%


  • Surgical approaches

    • Complete wide excision with tumor-free margins

  • Adjuvant therapy

    • Postoperative radiotherapy may be given for large, incompletely excised neoplasms


  • High-grade sarcoma

  • Worse prognosis than dedifferentiated liposarcoma

  • Better prognosis than high-grade myogenic sarcomas

  • Deep-seated large neoplasms are associated with worse prognosis

  • > 20 mitoses per 10 high-power fields and necrosis are associated with worse prognosis


General Features

  • Firm, often multinodular neoplasms

  • White to yellow cut surfaces

  • May show myxoid areas

  • May show areas of tumor necrosis


Histologic Features

  • Well-circumscribed, nonencapsulated, or ill-defined infiltrative neoplasms

  • High-grade sarcoma associated with variable number of pleomorphic lipoblasts

  • Sheets or single pleomorphic lipoblasts

  • Pleomorphic lipoblasts contain enlarged, hyperchromatic nuclei scalloped by cytoplasmic vacuoles

  • Sarcomatous component contains atypical spindled, round, and pleomorphic tumor cells

  • Numerous mono- and multinucleated tumor giant cells

  • High degree of nuclear atypia

  • Numerous mitoses

  • Areas of tumor necrosis are often present

  • Intermediate- or high-grade myxofibrosarcoma-like areas may be present

  • Intra- and extracellular eosinophilic droplets (represent lysosomal structures) are noted

  • Rarely prominent inflammatory infiltrate is evident

  • Epithelioid pleomorphic liposarcoma variant

    • Contains solid, cohesive sheets of epithelioid tumor cells

    • Foci of atypical lipogenic cells

    • Variable number of pleomorphic lipoblasts

  • Small round cell variant

    • Small round tumor cells

    • Variable number of pleomorphic lipoblasts

Predominant Pattern/Injury Type

  • Hypercellular

Predominant Cell/Compartment Type

  • Lipoblast

  • Undifferentiated, pleomorphic

Jul 9, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Pleomorphic Liposarcoma
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