- Bone island is aka enostosis
- A bone island is a focus of compact bone located in cancellous bone.
- Benign entity that is usually found incidentally on imaging studies
- Histologically, bone islands are intramedullary foci of normal compact bone with haversian canals and "thorny" radiations that merge with the trabeculae of surrounding normal cancellous bone.
- Most commonly identified in the pelvis, long bones, ribs, and spine.
 Imaging Findings
 Plain films
- Round or ovoid intramedullary sclerotic foci.
- Long axis of a bone island typically parallels the long axis of the involved bone. Bone islands appear homogeneously sclerotic with “thorny” radiating bone spicules that extend from the center of the lesion and blend with the trabeculae.
- Same as above for plain films
- Dark on all pulse sequences
 See Also
 External Links
Regalado, Sidney. E-medicine radiology article