CHONDROSARCOMA

CHONDROSARCOMA

• Chondrosarcoma is a malignant tumor where the tumor cells produce cartilage matrix

• Age – in adults in 5th and 6th decade of life

• Site – Axial skeleton (more aggressive), medullary cavity of femur, humerus, ribs and rarely digits

• Imaging –

  • They are located in metaphysis and extend into diaphysis producing radiolucent defect with scalloped inner cortex

  • Thickening and inequality of the cortex are common radiographic finding

  • Punctuate and stippled calcification are characteristic

• Gross –

  • They are lobulated  with grayish white or blue on cut section.

  • Focal calcifications may be pressent

  • Areas of mucoid degeneration or necrosis may occur.

• MIcroscopy

  • Chondrosarcomas are graded into 3 groups

    • Grade I – Low grade chondrosarcomas resembling enchondroma. Microscopic evidence of invasion into the adjacent bone and foci of entrapped entrapped bone within the tumor help in distinguishing it from enchondroma

    • Grade II – Increased cellularity with increased nuclear size and distinct nucleoli. Focal myxoid change and binucleated cells can be seen

    • Grade III – High grade chondrosarcoma characterized by marked cellular atypia, hypercellularity and high mitotic activity

  • more than 10% of chondrosarcoma undergo dedifferentiation showing malignant spindle cells and bizarre giant cells

• Variants

• Mesenchymal chondrsarcoma

  • Age– 2nd and 3rd decades of life

  • Site – Any bone can be affected but has predilection for the maxilla, mandible and ribs

  • 1/3rd of lesions are present in soft tissue

  • Imaging – osteolytic lesion with irregular calcification

  • Morphology

    • Gross – grayish white or yellow tumor mass

    • Microscopy –

      • Shows biphasic pattern

      • majority is composed of small, uniform, round to spindle shaped cells with perivascular arrangement of cells that gives hemangiopericytoma like pattern

      • In between the cells areas of cartllage or chondroid matrix is seen

    • most common site of metastasis is lungs, but can metastasize to bones and soft tissue

• Clear cell chondrosarcoma

  • least common variant of chondrosarcomas

  • It is a low grade malignant tumor presenting in young adults, predominantly men

  • Location – epiphysis of long bones commonly in the upper femur

  • Imaging – well circumscribed mixed lucent and sclerotic defects often with a thin sclerotic border and scattered calcification

  • Microscopy

    • Tumor cells have abundant clear or pale eosinophilic, vacuolated cytoplasm rich in PAS positive glycogen which often lies between heavily calcified cartilage matrix and woven bone

    • scattered giant cells are present

  • IHC – strongly positive for S-100

  • prognosis – they are indolent but locally aggressive.