Chondroblastoma

Chondroblastoma (synonyms: Codman tumor; ICD-10-GM D16.9: Bone and articular cartilage, unspecified) is a benign (benign) neoplasm (neoplasm) of bone arising from the chondroblasts (cartilage-forming cells).

Chondroblastoma is a primary tumor. Typical for primary tumors is their respective course and that they can be assigned to a certain age range (see “Frequency peak”) as well as a characteristic localization (see under “Symptoms – complaints”). They occur more frequently at the sites of most intensive longitudinal growth (metaepiphyseal/articular region). This explains why bone tumors occur more frequently during puberty. They grow infiltratively (invading/displacing), crossing anatomical boundary layers. Secondary bone tumors also grow infiltratively, but usually do not cross boundaries.

Sex ratio: boys/men are more than twice as likely to be affected as girls/women.

Peak incidence: chondroblastoma occurs predominantly between the ages of 10 and 20 years (approximately 80% in the 2nd decade of life).

Chondroblastoma is a very rare benign bone tumor. It accounts for less than 1% of all bone tumors and 4% of all cartilage tumors.

The course and prognosis depend on the location and extent of the chondroblastoma. Initially, it is possible to wait and observe (“watch and wait” strategy). The chondroblastoma grows slowly. Only in the further course does it cause symptoms. Although it is a benign tumor, chondroblastoma can behave aggressively, i.e. it spreads destructively (destroying the bone structure). In a few cases (< 1%), metastasis (formation of daughter tumors) is observed, particularly to the lungs, and rarely to bone, soft tissue, diaphragm, and liver. Almost always, metastases occur postoperatively (after surgery/transplanted metastases) or after local recurrence. Metastasis may still occur after more than 30 years. The metastases have to be resected. In the majority of cases, patients subsequently show normal survival. In this respect, chondroblastoma resembles the giant cell tumor of bone (osteoclastoma).In very few cases, recurrent chondroblastoma has degenerated to date. In general, the prognosis for patients with chondroblastoma is good.

Recurrences (recurrence of disease) occur in 5 to 15%, usually within the first two years after surgical removal of the chondroblastoma. Second recurrences are rare.