Pleura
Other tumors
Liposarcoma

Author: Vaidehi Avadhani, M.D. (see Authors page)

Revised: 26 March 2018, last major update March 2014

Copyright: (c) 2003-2018, PathologyOutlines.com, Inc.

PubMed Search: Liposarcoma pleural

See also: Soft tissue chapter
Cite this page: Avadhani, V. Liposarcoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/pleuraliposarcoma.html. Accessed September 22nd, 2018.
Definition / general
  • Very rare, < 20 cases reported; more common in extremities and retroperitoneum
  • Ages 19 - 80 years, mean age 49 years, usually men
  • Usually myxoid subtype
Etiology
  • Origin: residual rests of primitive mesenchymal tissue
Clinical features
  • Presenting clinical complaints: shortness of breath, cough, pleurisy
Diagnosis
  • Distinction of pleural liposarcoma from liposarcomas arising from chest wall or mediastinum requires careful radiographic and surgical evaluation
Prognostic factors
  • Difficult to determine due to rarity but positive surgical margins are considered important as in other chest wall sarcomas
Case reports
Treatment
  • Low grade tumors: complete surgical resection with tumor free margins
  • High grade tumors: adjuvant therapy may be considered
Gross description
  • Tumor size ranges from 3 cm to greater than 10 cm
  • Yellow-gray, rubbery, nodular, lobulated, gelatinous or mucoid
Microscopic (histologic) description
  • Most common histologic subtypes: myxoid and well differentiated
  • Criteria for a lipoblast:
    1. Hyperchromatic indented nucleus
    2. Lipid rich droplets in cytoplasm
    3. Appropriate histologic background
  • Classification:
    • Atypical lipomatous tumor / well differentiated liposarcoma (ALN / WDL): predominantly composed of mature fat with a variable number of atypical hyperchromatic spindle cells and multivacuolated lipoblasts
      • Subtypes include:
        1. Lipoma-like
        2. Sclerosing
        3. Inflammatory
    • Dedifferentiated liposarcoma: atypical lipomatous tumor / well differentiated liposarcoma juxtaposed to high grade nonlipogenic sarcoma (most commonly high grade fibrosarcoma or undifferentiated pleomorphic sarcoma)
    • Myxoid liposarcoma: multinodular mass composed of spindle cells or fusiform cells in a myxoid matrix with a delicate plexiform capillary vascular network
    • Pleomorphic liposarcoma: areas of undifferentiated pleomorphic sarcoma and pleomorphic lipoblasts
    • Spindle cell liposarcoma: very rare
Microscopic (histologic) images

Images hosted on other servers:


Myxoid / round cell liposarcoma


Well differentiated liposarcoma

Pleomorphic

Mixed

Dedifferentiated

Positive stains
  • CDK4 and MDM2 (nuclear stains) are positive in atypical lipomatous tumor / well differentiated liposarcoma but may also be positive in spindle cell / pleomorphic lipoma, nonlipomatous sarcomas (e.g. MPNST) and histiocyte nuclei
  • Vimentin
Negative stains
Molecular / cytogenetics description
  • ALN / WDL are characterized by giant marker and ring chromosomes - amplified sequences of 12q13-15
    • MDM2 amplification evaluated by FISH is highly specific and sensitive for ALN / WDL
  • Myxoid liposarcomas are characterized by t(12:16)(q13;p11), resulting in fusion of DDIT3 gene on #12 with FUS gene on #16; rare translocation is t(12;22)
Differential diagnosis