Secondary bone lesions in the affected limb in osteosarcoma (skip lesions), its classification and prognosis

Secondary bone lesions in the affected limb (SLAL) could appear after the limb-saving operation for osteosarcoma. If limb-saving surgery with a reduced surgical margin is contributing to the appearance of SLAL and eventually make the prognosis worse, we should prefer more extensive surgery. On the other hand, if SLAL is closely related to the systemic metastases, SLAL should be treated mainly by chemotherapy and limb saving-operation is still preferable.

The authors analyzed their patients with SLAL in order to get the optimum guidelines for the surgical treatment. 116 patients with osteosarcoma arising in the extremities were retrospectively reviewed. Among them 106 primary lesions were resected with a margin of more than 5 cm apart from the lesion.

Twelve patients (10%) showed SLAL in various timing of the patients' clinical course. All SLAL were accompanied with the distant metastases. In addition, a long survivor who had lung metastases showed SLAL appeared before lung metastasis.

We concluded that, SLAL was equal to systemic metastases. Therefore, the surgical margin which is more than 5 cm apart from the primary lesion is not enough to prevent SLAL. Only intensive chemotherapy is suspected to be useful to treat the undetectable SLAL on initial examination.