MedGen

Aneurysmal bone cysts are benign primary or secondary lesions that are rapidly expansive and locally destructive. They are located in the posterior elements of the vertebral column or the flat or long bones of patients under 30 years of age. The cysts are blood-filled and separated by septa containing spindle cells, trabeculae of bone, and osteoclastic giant cells (Biesecker et al., 1970). Histopathologically and radiographically, aneurysmal bone cysts are similar to telangiectatic osteosarcoma from which they must be differentiated. [from OMIM]

A form of primary hypertrophic osteoarthropathy, a rare hereditary disorder with characteristics of digital clubbing, pachydermia and subperiosteal new bone formation associated with pain, polyarthritis, cutis verticis gyrata, seborrhoea and hyperhidrosis. Three forms have been described: a complete form with pachydermia and periostitis, an incomplete form with evidence of bone abnormalities but lacking pachydermia, and a forme frusta with prominent pachydermia and minimal-to-absent skeletal changes. The disease typically begins during childhood or adolescence and may stabilise after 5-20 years of progression, or progress constantly. Mutations in the HPGD gene (4q33-q34) have been identified. The gene encodes 15-hydroxyprostaglandin dehydrogenase (15-PGDH), the main enzyme of prostaglandin degradation. Inherited as an autosomal recessive trait. [from SNOMEDCT_US]