In children, the most common primary malignancies to metastasize to bone include neuroblastoma and leukemia or lymphoma. Metastatic neuroblastoma should be at the top of the differential in a child < 5 years of age who presents with a neoplastic bony lesion (it is far more common than a primary bone lesion in this age group).

Leukemia and metastatic lymphoma have a predilection for the metaphyseal regions of long bones where they can cause bony destruction. Both will often present radiographically as lucent metaphyseal bands, which have been termed "leukemic lines."

Acute Lymphocytic Leukemia is the leading cause of cancer in the pediatric population. Radiographically detectable lesions are seen in up to one-half of all childhood leukemic cases. These lesions are not deemed metastases, but rather primary bone involvement from neoplastic proliferation of marrow elements.

Primary bone lymphoma is rare in children.

Metastatic neuroblastoma in a 2-year-old female who complained of pain in the right knee. Left, AP radiograph shows an asymmetric permeative lucency within the right distal femur. Right, Lateral view of the right knee shows the permeative process.