Osteosarcoma

Osteosarcoma can occur in any bone the foot. The calcaneus is the most commonly involved bone. At peak age of incidence is around 20, but the very young and the very old are also affected.

The patient presents with insidious pain and, eventually, a mass. Initially, the pain may be intermittent and related to a minor injury or exercise activity, and thus the problem is misdiagnosed as a common sprain or strain.

The pain will become persistent with time and begin occurring at night. Radiographs will initially reveal a subtile mixed lysis and sclerosis, followed by increasing sclerosis, permeation, destruction, and expansion into the adjacent soft tissues with bone formation in the soft tissue mass.

The differential diagnosis includes other sarcoma such as Ewing sarcoma and synovial sarcoma as well as metastasis.

Plain radiographs, CT scan, MRI scan, technetium 99 bone scan, and a CT scan of the chest are required to determine the local extent and stage of the tumor.

Most osteosarcomas present in stage IIB , which is defined as a tumor that has broken out of its compartment of origin, but where metastasis have not yet occurred.

Prognosis for osteosarcoma depends strongly tumor grade and stage at presentation. Low-grade tumors are associated with a proximally 90% long-term survival.

High-grade tumors have an overall survival of approximately 60%. Survival in patients with metastasis is poor.

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