IMPORTANT LEARNING POINTS: Radiographically, endosteal and periosteal thickening of the diaphyses of long bones. The result is narrowing of the medullary cavity. The metaphyses can become affected, but typically the epiphyses are spared. Sclerosis of
the skull base can be present, leading to hearing impairment
owing to progressive stenosis of the external auditory canal, and
foraminal stenosis causing cranial nerve dysfunction. These characteristics are seen both in Erdheim-Chester disease (non-Langerhans cell histiocytosis), and in progressive diaphyseal dysplasia (Camurati-Engelmann disease).
lateral radiograph of right upper extremity. Marked cortical thickening is present along the shafts of the radius and ulna. Similar but minimal changes are also present in the shaft of humerus. No fracture or erosive process is seen.