Chondromyxoid fibroma

Chondromyxoid fibroma is a rare benign chondro-osseous tumour typically found in the metaphysis of teenagers or young adults.

General

• Uncommon and benign.
• Teenagers or young adults.

Gross

• Metaphyseal lesion - classic location.
• Well-circumscribed.
• Fragments of white-grey rubbery tissue

Microscopic

Features:

• Spindle cells or stellate cells in a myxoid or chondroid stroma.
• Lobules with hypocellular centers and hypercellular peripheries.
• Giant cells in the hypercellular periphery
• Scattered calcifications
• No true hyaline cartilage matrix
• Lack of mitotic activity

DDx:

• Phosphaturic mesenchymal tumour - case report.
• Chondroblastoma
  • Also produces immature cartilage but
  • Epiphyseal location
  • Chicken-wire calcifications
• Chondrosarcoma
  • Mature hyaline cartilage formation
  • Tumor permeation of the surrounding bone
  • Mitotic activity

Images:

• Chondromyxoid fibroma - low mag. (webpathology.com).
• Chondromyxoid fibroma - high mag. (webpathology.com).
• Tumor Library [1]
• Tumor Library [2]
• Tumor Library [3]
• Tumor Library [4]
• Tumor Library [5]
• Tumor Library [6]

Molecular

• Activating rearrangements of GRM1 (metabotropic glutamate receptor 1)

See also

• Chondro-osseous tumours.