If present, the cystic fluid is rust or straw-colored. Chondroblastoma is made up of uniform, polygonal cells that are closely packed. These primitive cells are derived from the epiphyseal cartilage plate and have abundant cytoplasm. There is little mitotic activity. The rapid proliferation of immature chondrocytes does not create lacunae or formal cartilage matrix.
Giant cells are often present.
Treatment of chondroblastoma is biopsy and curettage with possible use of adjuvant liquid nitrogen or phenol, or a mechanical burr. It may be necessary to reconstruct articular surfaces due to subchondral erosion. Any joint invasion is usually secondary to previous instrumentation. All pulmonary nodules should be excised.