These tumors represent benign tumors of the hyaline cartilage
May represent as single or multiple lesions.
Enchondromatosis or Ollier's disease is a familial disease which manifests with multiple enchromas.
In Maffucci's syndrome, multiple enchondromas are associated with hemangiomas.
Single lesions rarely undergo sarcomtous transformation. The lesions in the hand and feet may recur if incompletely excised. The sarcomatous transformation is frequent in syndromes associated with multiple enchondromas.
Clinically, these tumors are usually asymptomatic, however, they may produce pain or the deformity of the bone and may lead to bone fracture.
The single lesions usually occur in the bones of the hand and feet These may arise in other bones but rarely occur in the skull.
Grossly, these tumors appear as firm, slightly lobulated, gray and translucent tumors, which are less than 2 cm in diameter. These tumors may lead to the destruction of the cortical bone and expansion of the bone, however, penetration of the adjacent bone should be regarded with the suspicion of malignancy.
Microscopically, these tumors are made of hyaline cartilage within a vascularized fibrous stroma. Cartilage cells are enclosed within lacunar spaces and are dispersed randomly in the cartilagenous matrix. Multinucleated giant cells or marked cellular atypia should raise the suspicion of malignancy. The tumors may exhibit foci of calficification and ossification. The cells within such ossified foci do not exhibit atypia as seen in typical osteosarcomas.