Unusual Bone Metastasis Neuroblastoma in Adolescent With Unidentified Primary Site

We present a rare case of bone metastatic Neuroblastoma without a diagnosis of an identifiable primary lesion in a 16-year-old patient who presented with intermittent right knee pain and soft tissue swelling for 7 months. Initial radiologic examinations revealed a primary bone tumor in the distal metaphyseal-diaphyseal region of the femur, and a follow-up CT of the chest, abdomen, and/or pelvis revealed no evidence of a solid mass. The first bone biopsy provided inconclusive results, leading to a misdiagnosed osteosarcoma. The revisiting from St. Jude children's research hospital concluded metastasis from a Neuroblastoma. The patient was subsequently classified into the high-risk group and given standard treatment.