Dedifferentiated Liposarcoma

Dedifferentiated Liposarcoma

Thomas Mentzel, MD

Gross pathology photograph shows an abrupt transition from atypical lipomatous tissue image to a larger, nonlipogenic sarcomatous component image.

Hematoxylin & eosin shows dedifferentiated nonlipogenic sarcoma (left) with an abrupt transition from atypical lipomatous tumor (right). Note the sharp demarcation between the 2 components.



  • Dedifferentiated liposarcoma (DDLS)


  • Malignant lipogenic neoplasm with abrupt or gradual transition from atypical lipomatous tumor to nonlipogenic sarcoma of variable histology



  • Incidence

    • Occurs in ˜ 10% of cases of atypical lipomatous tumor

    • 90% arise de novo, 10% in local recurrences

    • Retroperitoneum, intraabdominal cavity are more frequently involved than extremities, spermatic cord, head/neck region, trunk

    • Mainly in deep soft tissues

    • Very rare in subcutaneous and dermal tissues

    • Probably represents time-dependent phenomenon

  • Age

    • Middle-aged to elderly patients

  • Gender

    • M = F


  • Large, painless mass

  • Slowly growing neoplasm

  • Often longstanding mass exhibiting recent increase in size


  • Surgical approaches

    • Complete excision with tumor-free margins


  • Recurs locally in ≥ 40% of cases

  • Distant metastases observed in 15-20% of cases

  • Overall mortality 25-30% at 5-year follow-up

  • Anatomic location is most important prognostic factor

  • Retroperitoneal, intraabdominal lesions exhibit worst clinical behavior

  • Superficial neoplasms have good prognosis

  • Amount and morphological grade of nonlipogenic areas not of prognostic importance


General Features

  • Best diagnostic clue

    • Coexistence of fatty and non-fatty-solid components

  • Location

    • Retroperitoneum, intraabdominal cavity, deep soft tissues

  • Size

    • Large size, usually > 5 cm

  • Morphology

    • Circumscribed


General Features

  • Large, multinodular yellow mass with solid, often tangray or gray-white nonlipomatous areas

Sections to Be Submitted

  • Sections of both components must be sampled carefully


  • May reach large size, especially in abdomen and retroperitoneum


Histologic Features

  • Abrupt or gradual transition from atypical lipomatous tumor (of any subtype) to nonlipogenic sarcoma

  • Varying size and shape of lipogenic tumor cells

  • Presence of enlarged and hyperchromatic nuclei in lipogenic component

  • Nonlipogenic sarcoma component shows broad morphologic variation

  • High-grade nonlipogenic sarcoma component (pleomorphic sarcoma, intermediate- to high-grade myxofibrosarcoma-like areas)

  • Often presence of multinucleated giant cells

  • Increased proliferative activity

  • Low-grade nonlipogenic component (uniform fibroblastic spindle cells with mild nuclear atypia)

  • Heterologous differentiation in ˜ 10% of cases

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