Chondroid Lipoma

• Mostly female, slow growing, painless, benign

• Micro:

  • Well circumscribed, mixture of vacuolated cells, prominent chondromyxoid matrix and variable mature fat

  • No pleomorphism, atypia, atypical mitotic activity, or mature hyaline cartilage

  • May show hemorrhage and fibrosis

• IPX: S100+ in lipoblasts and adipocytes

• DDX:

  • Myxoid liposarcoma: chicken-wire vasculature,  no prominent cords or clusters of cells, t(12;16)

  • Extraskeletal myxoid chondrosarcoma: prominent fibrous septa, chondroblasts without  intracytoplasmic vacuoles, no mature fat, frequently mitoses and necrosis

Reference:

• Enzinger and Weiss's Soft Tissue Tumors, 5th Edition. By Drs. Sharon Weiss and John Goldblum. 2007