Soft tissue
Adipose tissue tumors
Liposarcoma
Pleomorphic liposarcoma
Author: Vijay Shankar, M.D.
Topic Completed: 1 August 2012
Minor changes: 2 October 2020
Copyright: 2002-2021, PathologyOutlines.com, Inc.
PubMed Search: Pleomorphic liposarcoma [title]
Table of Contents
Definition / general | Epidemiology | Sites | Case reports | Treatment | Clinical images | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Cytology description | Positive stains | Electron microscopy description | Molecular / cytogenetics description | Differential diagnosis | Additional referencesCite this page: Shankar V. Pleomorphic liposarcoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/softtissueadiposepleomorphiclipo.html. Accessed January 22nd, 2021.
Definition / general
- Widespread high grade, pleomorphic tumor cells with some lipoblasts but no evidence of well differentiated liposarcoma
Epidemiology
- 5% of all liposarcomas
- No gender preference
- Median age 54 - 70 years; rare in childhood
- Associated with radiation therapy or neurofibromatosis
Sites
- Thigh (29%), internal trunk (21%), limb girdles (18%), upper extremity (16%), thoracoabdominal wall (10%)
- Often deep seated or extracompartmental
Case reports
- 42 year old man with pericardial tumor (Interact CardioVasc Thorac Surg 2010;11:325)
- 47 year old woman with breast mass (Indian J Pathol Microbiol 2011;54:124)
- 70 year old male with pectoral wall mass (J Can Res Ther 2009;5:315)
- 71 year old woman with tumor of foot (Diagn Pathol 2008;3:15)
- 72 year old man with epithelioid tumor (Pathol Res Pract 2004;200:545)
- Post-radiotherapy for epithelioid sarcoma (Pathol Oncol Res 2000;6:287)
Treatment
- Wide local excision or amputation with postoperative radiotherapy (Am J Surg Pathol 2004;28:1257), also chemotherapy
- Aggressive; often recurs locally (40%), metastasizes (40%), causes death (35%)
- 5 year overall survival 60%
- Poor prognostic factors: age 60+, truncal (central) location, deep, size > 5 cm, vascular invasion, incomplete excision (Am J Surg Pathol 2002;26:601)
Clinical images
Images hosted on other servers:
Pectoral wall mass
Gross description
- Often large (median 8 - 10 cm, up to 23 cm), multinodular, white-yellow
- Areas of hemorrhage and necrosis common
- Usually deep (subfascial), often myxoid or necrotic areas
Gross images
Images hosted on other servers:
Infiltrating gluteus muscle
Retroperitoneum
Microscopic (histologic) description
- Well circumscribed but non-encapsulated with infiltrative borders
- At least focal typical liposarcomatous areas
- Pleomorphic cells cover > 65% of cut surface with MFH-like, round cell liposarcoma-like (without vascular network), spindle cell liposarcoma-like or epithelioid cells (Mod Pathol 1999;12:722)
- Usually high grade with enlarged round to bizarre nuclei
- Tumor necrosis common
- Median 25 mitotic figures / 10 HPF
- May have neutrophils within giant cells, hemangiopericytic foci, extra- and intracellular hyaline droplets
- Epitheloid variant often confused with carcinoma
Microscopic (histologic) images
AFIP images
Lipoblasts present
Vacuolated lipoblasts
Myxoid stroma with markedly pleomorphic cells
Pleomorphic round cells
MFH-like areas
Contributed by Mark R. Wick, M.D.
Images hosted on other servers:
Pectoral wall
Cytology description
- Pleomorphic spindle cells of high grade sarcoma with occasional lipoblasts
Positive stains
Electron microscopy description
- Abundant coalescing lipid droplets, numerous cytoplasmic organelles
Molecular / cytogenetics description
- Complex karyotype
- Shares similar genomic imbalances with myxofibrosarcoma (Lab Invest 2005;85:176)
- Epithelioid variant rarely has t(12;16)(q13;p11) - TLS-CHOP, more commonly seen in myxoid and round cell liposarcoma (Histopathology 2005;46:334)
Differential diagnosis
- Dedifferentiated liposarcoma: also has well differentiated component
- Metastatic carcinoma: keratin+ or other evidence of epithelial differentiation, no liposarcomatous differentiation
- MFH-pleomorphic: no definite lipoblasts
- Pleomorphic lipoma: ropy collagen, no / rare mitotic figures
- Pleomorphic rhabdomyosarcoma: skeletal muscle differentiation
Additional references
