Soft tissue
Adipose tissue
Well differentiated myxoid liposarcoma

Author: Vijay Shankar, M.D. (see Authors page)

Revised: 9 August 2016, last major update August 2012

Copyright: (c) 2002-2016, PathologyOutlines.com, Inc.

PubMed Search: Well differentiated myxoid liposarcoma

Definition / General
  • Low grade tumor with primitive non-lipogenic mesenchymal cells, signet ring lipoblasts and prominent myxoid stroma with branching vascular pattern
Terminology
  • Also called paucicellular myxoid liposarcoma
Epidemiology
  • Peaks in 30’s and 40’s
  • May occur in children, very rarely in elderly
Sites
  • Usually thigh and lower extremity of young adults
  • Retroperitoneal involvement is rare
Case Reports
Treatment
  • Median survival 105 months (Ann Surg Oncol 2007;14:1507)
  • Pure tumors (without round cells) have low grade behavior with only rare metastases
  • Poorer prognosis if round or pleomorphic cells
Gross Images

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Well differentiated myxoid liposarcoma



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Recurrence of the adipose mass with kidney involvement

Well circumscribed white tumor

Lobulated gray-white tumor within skeletal muscle

Micro Description
  • Low grade and paucicellular with monomorphic, stellate or fusiform cells without atypia
  • Prominent chicken wire vasculature (delicate thin walled arborizing and curving capillaries)
  • Numerous signet ring lipoblasts, particularly at periphery of lobules, has mucoid matrix rich in hyaluronidase sensitive acid mucopolysaccharides, may have large mucoid pools
  • Lymphangioma-like cystic degeneration is relatively specific
  • Rarely metaplastic cartilage or cartilage with TLS-CHOP fusion gene (Appl Immunohistochem Mol Morphol 2007;15:477)
  • No / rare mitotic figures
Micro Images

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Lipoblasts, myxoid stroma and branched capillaries

Cords of cells resembling myxoid chondrosarcoma



Resembles pulmonary edema due to large irregular cystic spaces, some with granular eosinophilic material

Hyalinized collagenous stroma (rare finding)



Large (mature) and small fat cells

Hypocellular zones: left-small artery, middle-veins, right-transition between cellular and hypocellular areas

Signet ring lipoblasts



Images hosted on other servers:

Lipoblasts, myxoid stroma and branched capillaries



Metastases

Lipoblasts, myxoid stroma and branched capillaries



Lipoblasts

Cytology Description
Electron Microscopy Description
  • White adipose tissue, aggregates of 60-Angstrom intermediate filaments and large masses of glycogen (Am J Clin Pathol 1979;72:521)
  • Cells have investing basal lamina, pinocytotic vesicles, cytoplasmic glycogen and cytoplasmic lipid (Am J Surg Pathol 1980;4:163)
  • Resembles lipoblastoma
Differential Diagnosis