%0 Case Reports %T Multifocal osteoclast-rich tumour in Paget bone disease and conventional giant cell tumour, two genetically distinct entities? Sequencing from a single case. %A Haefliger S %A Bubbear J %A Davies C %A Cottone L %A Amary F %A Tirabosco R %A Cortes-Ciriano I %A O'Donnell P %A Flanagan AM %J Skeletal Radiol %V 53 %N 1 %D 2024 Jan 13 %M 37310481 %F 2.128 %R 10.1007/s00256-023-04369-6 %X Paget disease of bone is a metabolic disorder with a strong genetic component, characterised by pronounced disorganised bone remodelling. Complications of this disease include an increased risk of developing bone neoplasms. Here, we describe the case of a 60-year-old Italian patient with Paget disease of bone, presenting with an osteoclast-rich tumour. Our analysis of this entity, based on the clinical, morphological and genetic data (whole exome sequencing), suggests that osteoclast-rich lesions in Paget disease of bone are genetically distinct from classical giant cell tumour of bone. We discuss the importance of differentiating these osteoclast-rich lesions.