Yellow discoloration of the osteoid seams of the partly demineralised trabecular bone in the site of the osteolytic cancer metastasis was observed. Intralesional hemorrhage with massive breakdown of the red cells and local release of bilirubin caused characteristic colour changes of unmineralised osteoid. Mineralised osteoid had unchanged colour. No morphological changes of bone cells were recognised. Yellow osteoid developed as a result of local high bilirubin concentration in the neighbourhood of bone trabecullae with unmineralised osteoid seams.