Chondromyxoid fibroma

Chondromyxoid fibroma is benign neoplasm, characterised by the presence of lobules of spindle shaped cells and stellate cells embedded in the myxoid matrix
Incidence – less than 0.5% of all tumors and 1.6% of all benign tumors
Clinical fatures:
- Presenting symptom is pain. Swelling is less common
- Sex – slight male predominance
- Age –second and third decades of life
- Sites – 45% of lesions involve long bones most commonly proximal tibia
  - Other sites are
    - Iliac wing
    - Rib
    - In hands and feet metatarsals are involved and metacarpals are rarely involved.
- Radiographic finding:
  - Typical radiographic feature – eccentrically located lucent lobulated defect in the metaphysis of long bone
  - Epiphysis is involved in the small bones
  - Mineralization is usually absent but CMF arising on the surface of long bones are heavily mineralized
  - Tumor may extend into epiphysis or into diaphysis
  - Cortex is thinned out and margins are sharply demarcated
  - 50% of tumors shows sclerotic rim
  - Periosteal new bone formation is rare.
Gross finding:
- Specimen has semitranslucent appearance due to myxoid matrix
- Tumor is well circumscribed, lobulated and appears to be retracted from surrounding bone
Microscopic findings:
- It has characteristic lobulated growth pattern
- Lobules are large or microlobular pattern may be seen
- Lobules contain spindle and stellate shaped cells embedded in myxoid stroma
- Cells have abundant pink cytoplasm
- Central part of lobules is hypocellular whereas periphery shows hypercellualarity with proliferation of polyhedral cells and clusters of benign giant cells
- Matrix stains light blue. Well formed cartilage is seen in less than 20% of cases
- Calcifications may be present as fine granules or plaque like
- Lesions on bone surface are heavily calcified
- Secondary aneurysmal bone cyst is unusual
Differential diagnosis:
- Chondrosarcoma – has lobulated growth pattern with myxoid matrix and nuclear pleomorphism
- Hypocellular and hyercellular areas are not feature of chondrosarcoma
Treatment :
- - Curttage or limited resection
  - Recurrence is seen in 20% of patients

Reference:

Krishnan Unni, Carrie Y.Inwards, Julia A.Bridge, Lars –Gunnar kindblom, Lester E.Wold. Chondromyxoid fibroma. In : Cartilaginous lesions. Tumors of the bones and joints. AFIP Atlas of tumor pathology.Series 4.67-73

CHONDROMYXOID FIBROMA

Chondromyxoid fibroma is benign neoplasm, characterised by the presence of lobules of spindle shaped cells and stellate cells embedded in the myxoid matrix

Incidence – less than 0.5% of all tumors and 1.6% of all benign tumors

Clinical fatures:

Presenting symptom is pain. Swelling is less common

Sex – slight male predominance

Age –second and third decades of life

Sites – 45% of lesions involve long bones most commonly proximal tibia

Other sites are

Iliac wing

Rib

In hands and feet metatarsals are involved and metacarpals are rarely involved.

Radiographic finding:

Typical radiographic feature – eccentrically located lucent lobulated defect in the metaphysis of long bone

Epiphysis is involved in the small bones

Mineralization is usually absent but CMF arising on the surface of long bones are heavily mineralized

Tumor may extend into epiphysis or into diaphysis

Cortex is thinned out and margins are sharply demarcated

50% of tumors shows sclerotic rim

Periosteal new bone formation is rare.

Gross finding:

Specimen has semitranslucent appearance due to myxoid matrix

Tumor is well circumscribed, lobulated and appears to be retracted from surrounding bone

Microscopic findings:

It has characteristic lobulated growth pattern

Lobules are large or microlobular pattern may be seen

Lobules contain spindle and stellate shaped cells embedded in myxoid stroma

Cells have abundant pink cytoplasm

Central part of lobules is hypocellular whereas periphery shows hypercellualarity with proliferation of polyhedral cells and clusters of benign giant cells

Matrix stains light blue. Well formed cartilage is seen in less than 20% of cases

Calcifications may be present as fine granules or plaque like

Lesions on bone surface are heavily calcified

Secondary aneurysmal bone cyst is unusual

Differential diagnosis:

Chondrosarcoma – has lobulated growth pattern with myxoid matrix and nuclear pleomorphism

Hypocellular and hyercellular areas are not feature of chondrosarcoma

Treatment :

Curttage or limited resection

Recurrence is seen in 20% of patients

Reference:

Krishnan Unni, Carrie Y.Inwards, Julia A.Bridge, Lars –Gunnar kindblom, Lester E.Wold. Chondromyxoid fibroma. In : Cartilaginous lesions. Tumors of the bones and joints. AFIP Atlas of tumor pathology.Series 4.67-73