Cartilagenous cap thin or non-existent in adults. When multiple, mulple hereditary exostosis is suspected. When solitary, developmental physeal defect vs. neoplasm. Often discovered early as a painless mass. Femur, humerus, tibia most commonly involved but occurs elsewhere.
Exostoses commonly point away from the joint.
Malignant degeneration in approx. Pain, growth, bone erosion, irreg. Normal bone scan virtually excludes malignant degeneration.