Multiple myeloma (MM) and osteosarcoma (OS) are two common bone malignancies, however, the simultaneous occurrence of both primary bone tumors in the same patient has not been reported in the United States to date. We present a unique case in which both malignancies present concurrently in a 72-year-old man. Results of spinal magnetic resonance imaging (MRI), radiographic skeletal survey, and hematological workup established the initial diagnosis of MM. Approximately three months later, the patient was admitted with severe right hip pain and shortness of breath and was evaluated with computed tomography (CT) of the right hip, abdomen, pelvis, and chest, revealing an osseous mass with a "sunburst" pattern in the right hip, and several calcified nodules in the lungs. Subsequent wedge resection and histological evaluation of the lung nodules confirmed the diagnosis of metastatic OS to the lungs, with a presumptive diagnosis of primary OS of the right hip. The clinical findings and imaging characteristics in this case are presented. Two similar cases found in the literature are also briefly discussed. The findings of this case report suggest that, in rare instances, MM patients with sclerotic bone findings may have a concurrent diagnosis of OS.
Keywords: aggressive primary bone tumor; computed tomography; multiple myeloma; osteosarcoma; rare concurrent diagnosis.