=====Osteochondroma=====
Osteochondromas or “osteocartilaginous exostoses” are exophytic outgrowths from the parent bone surface that are composed of cortical and medullary bone with an overlying hyaline cartilage cap. 

Osteochondromas usually arise from the long bones and results from abnormal endochondral ossification
((Albrecht S, Crutchfield JS, SeGall GK. On spinal osteochondromas. J Neurosurg. 1992;77:247–52.))
((Sharma MC, Arora R, Deol PS, Mahapatra AK, Mehta VS, Sarkar C. Osteochondroma of the spine: An enigmatic tumor of the spinal cord. A series of 10 cases. J Neurosurg Sci. 2002;46:66–70. )).



====Classification====
Osteochondromas are classified in two distinct clinical settings; as either solitary lesions or multiple hereditary exostoses. The former usually have a tendency to arise from the metaphysis of the long bones, and are rarely found in the spine. 

see [[Spinal osteochondroma]]



====Clinical Features====
They can cause various signs and symptoms depending on their size and location
((Kitsolulis P, Galani V, Stefanaki K, Paraskevas G, Karatzias G, Agnantis NJ, Bai M: Osteochondromas: Review of the clinical, radiological and pathological features. In Vivo 22:633-646, 2008))
((Woertler K, Lindner N, Gosheger G, Brinkschmidt C, Heindel W: Osteochondroma: MR imaging of tumor-related complications. Eur Radiol 10:832-840, 2000)).