Intramedullary Osteosclerosis

A nonhereditary condition that effects the long bones of the lower extremities (tibia > femur, fibula). On imaging studies it presents with endosteal sclerosis extending into the medullary canal, possibly obliterating the canal. There is no associated periosteal reaction or soft tissue swelling. Bone scan will show intense radiopharmaceutical uptake.This condition is more common in women and usually presents as pain that is exacerbated by activity.

Differential diagnosis:
1. Ribbing disease - may look exactly the same. The main difference is that Ribbing disease tends to have a familial inheritance pattern (thought to be autosomal recessive).
2. Stress fracture - usually a focal sclerosis and periosteal reaction will be present.
3. Sclerotic metastases - patchy, discontinuous presentation, population tends to be older.
4. Progressive diaphyseal displasia (Camurati-Engelmann disease) - presents in young boys, has skull and vertebral body involvement, disease begins in the diaphysis of long bones and may extend to the metaphysis, has periosteal and endosteal sclerosis. 
5. Melorheostosis (Leri-Weill disease) - a sclerosing bone dysplasia which presents unilaterally in a long bone of the upper or lower extremity and may have associated soft tissue calcifications.

REFERENCES
Balkissoon ARA and Hayes CW. Intramedullary osteosclerosis. Radiology 1999;212:708-10.
Chanchairujira K, Chung CB, Lai YM, et al. Intramedullary osteosclerosis: imaging features in nine patients. Radiology 2001;220:225-30.