Liposarcoma

Pleura & peritoneum

Pleura other tumors

Liposarcoma

Topic Completed: 1 March 2014

Minor changes: 1 March 2019

Copyright: 2003-2019, PathologyOutlines.com, Inc.

PubMed Search: Liposarcoma pleural

See also: Soft tissue chapter

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Page views in 2020 to date: 446

Table of Contents

Cite this page: Avadhani V. Liposarcoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/pleuraliposarcoma.html. Accessed August 3rd, 2020.

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

42 year old man with pleural myxoid liposarcoma (J Cardiothorac Surg 2007;2:48)
45 year old woman and 67, 73 and 80 year old men with liposarcoma of pleural cavity (Arch Pathol Lab Med 2000;124:699)
47 year old man with massive pleural based tumor (Rev Port Pneumol 2011;17:275)
56 year old woman with pleural liposarcoma mimicking carcinoma in pleural effusion cytology (Acta Cytol 2010;54:601)
58 year old man with liposarcoma of pleural cavity (Thorac Cardiovasc Surg 2008;56:438)

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

Keratin, actin, desmin

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

Benign lipomatous lesions: fat atrophy, spindle cell lipoma, lipomatous solitary fibrous tumor
Metastases
Myxoid lesions: myxoma, myxoid undifferentiated pleomorphic sarcoma
Nonlipogenic sarcoma