Soft tissue
Adipose tissue tumors
Lipoma and variants
Chondroid lipoma


Topic Completed: 1 August 2012

Minor changes: 25 September 2020

Copyright: 2002-2020, PathologyOutlines.com, Inc.

PubMed Search: Chondroid lipoma

Vijay Shankar, M.D.
Page views in 2019: 2,470
Page views in 2020 to date: 2,065
Cite this page: Shankar V. Chondroid lipoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/softtissueadiposechondroid.html. Accessed October 24th, 2020.
Definition / general
  • Benign tumor of mature adipocytes, lipoblasts and myxochondroid stroma
  • Rare, slow growing, painless
  • First described in 1993 (Am J Surg Pathol 1993;17:1103)
Epidemiology
  • 80% female
  • Median age 36 years, range 14 to 70 years
Sites
  • Proximal extremities and limb girdles, rarely oral cavity
  • Intramuscular or subcutaneous
Case reports
Treatment
  • Excision is curative
  • Does not recur, metastasize or transform
Gross description
  • Median 4 cm, up to 11 cm, encapsulated, yellow or white
Gross images

Case #52

Well circumscribed mass



Images hosted on other servers:

Thigh mass

Yellow tumor

Microscopic (histologic) description
  • Well circumscribed, nests and cords of small to medium, multivacuolated cells resembling lipoblasts, chondroblasts or hibernoma cells within a prominent chondromyxoid matrix with variable mature fat, rarely metaplastic bone (Skeletal Radiol 2008;37:475)
  • Complex nuclear outlines
  • Usually prominent vasculature with variable wall thickness
  • May have hemorrhage and fibrosis, eosinophilic fibrinous matrix
  • No pleomorphism, no atypia, no / rare mitotic activity, no mature hyaline cartilage
Microscopic (histologic) images

AFIP images

Well circumscribed tumor

Mature fat cells are present

Clusters of small to medium cells with vacuolated cytoplasm



Case #52





Images hosted on other servers:

Various images

Cytology description
Positive stains
Negative stains
Electron microscopy description
  • Abundant intracytoplasmic lipid and glycogen and numerous pinocytotic vesicles, characteristic of white adipocytes (Am J Surg Pathol 1995;19:1272)
  • Resembles embryonal fat, and to a lesser extent, embryonal cartilage
  • Cells have knob like protrusions of cell membrane containing granular, amorphous and fibrillar material
  • No prominent mitochondria, no lysosomes (Hum Pathol 1995;26:706)
Molecular / cytogenetics description
Molecular / cytogenetics images

Case #52

t(11;16) plus other changes

Differential diagnosis
  • Lipoma with chondroid metaplasia: true cartilage present
  • Extraskeletal chondroma: distal extremities, mature hyaline cartilage, no fat
  • Extraskeletal myxoid chondrosarcoma: prominent fibrous septa; chondroblasts typically lack intracytoplasmic vacuoles, no mature fat; frequently has mitotic figures and necrosis
  • Mixed tumor: foci of epithelial differentiation, keratin+, no lipoblasts
  • Myxoid liposarcoma: different sites, usually no prominent cords or clusters of cells; has delicate plexiform capillary matrix, t(12;16)
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