Post-traumatic cysts and cyst-like lesions of bone.

We describe two patients with cyst-like lesions of bone that developed at sites of healed or healing fractures. One case showed histological features of a unicameral bone cyst, which, to the best of our knowledge, is a previously unreported finding in a post-traumatic cyst. It is suggested that there are two principal clinical and radiological types of post-traumatic cyst, of which each of our cases represents an example: (1) asymptomatic transient cortical lesions, found only in children, and (2) more central expanding lesions, found in a wider age group and associated with pain, swelling, and pathological fractures.