Osteochondromas may be solitary or multiple.

Osteochondromas can be sessile or peduculated.

Hereditary multiple osteochondromatosis (HME) is an autosomal dominant disorder.

Osteochondromas develop due to a beaked failure of constriction, with cortical overgrowth adjacent to the growth plate and usually grows away from joint and continues to grow until the growth plate closes and growth ceases at puberty.

 Complications:

Fractures

Bony deformities

Neurological and vascular injuries

Bursa formation

Malignant transformation –usually chondrosarcoma of low grade (1-25%) and more common in HME.

Suggestive of malignant transformation:

Pain

Cartilage cap 2 cm

Increase in size after closure of growth plate.

   Take Home Message: 

 Trevor'e disease-Dysplasia epiphysealis hemimelica(DEH) is characterized by ostochondromas arising in epiphysis and involves the joint.