Chondroblastoma of the acromion process of the scapula in a 28 y/o male. The bone is infiltrated by a whitish tumor resembling cartilage. The tumor penetrates the cortical bone and invades the soft tissue. This is a recurrent lesion 2 years after curettage. Local recurrence in long bone lesions is approximately 10% and is higher for chondroblastomas arising in flat bones, especially those lesions arising in the vicinity of the triradiate cartilage. Image copyright: pathorama.ch; used with permission.