- Associated with Avian Leukosis virus
- Variable eosinophilic trabeculae that extend from and efface the normal cortex
- Trabeculae lined by osteoblasts; rare osteoclasts
- Reversal lines (basophilic lines following the contour of the trabeculae) are common
- Frequent lacunae with osteoblasts
- Intertrabecular space filled with loose fibrovascular stroma (NOT marrow)


May see irregular to ovoid, basophilic, intracytoplasmic inclusions stacked within myocardial cells
