Chondroid Metaplasia of synovium affecting large joints
Nodules of hyaline cartilage
- formed in the subsynovial layer of joint capsules
Rare lesion
Most common in 20's and 30's
Sex: M > F (2:1)
Monoarticular
Malignant Fibrous Histiocytoma
Characterised by heterogenous population of pleomorphic spindle cells
- organised in a characteristic storiform or "starry night" pattern
Cell of origin unknown
- primitive mesenchymal cell
- allowing both features of a macrophage (hence histiocyte)
- and collagen producing cell (hence fibroblast)
Malignant cartilage producing tumour
20% of primary bone tumours
3rd most common
- 1 in 500 000
Relatively non-aggressive / usually Grade I
Average age 40
Male > Females
Arises de novo
Expansile pseudotumor of reactive hemorrhagic tissue arising in bone
- characterised by blood filled spaces separated by fibrous tissue
Primary 50%
- arise de novo
Secondary 50%
- in association with other tumours
- probably secondary to haemorrhage into 1° tumour
- GCT / chondroblastoma / osteoblastoma / osteosarcoma
No accepted definition
Chronic joint disorder in which there is progressive softening and disintegration of articular cartilage
- accompanied by new growth of cartilage and bone at the joint margins
- these changes secondary to mechanical failure of hyaline cartilage
Essentially no inflammatory component
Primary
Idiopathic