Lymphatic spread of pagetic osteogenic sarcoma detected by bone scan

Bone scans are widely utilized for detection of metastases from bone sarcomas. Technetium methylene diphosphonate scan ([(99m)Tc]MDP) is one of the most popular radiotracers used for that purpose. Lymphatic spread of bone sarcomas is unusual and often difficult to diagnose. Unfortunately, bone scans are not as sensitive in demonstrating lymphatic spread of sarcomas as they are at demonstrating hematogenous spread. A bone scan will often fail to demonstrate lymph nodes metastases until there is mineralization at the affected node. In this report, we highlight an interesting case of a patient with secondary osteogenic sarcoma (OS) from Paget's disease in the distal femur with non-ossified inguinal nodal metastasis diagnosed with [(99m)Tc]MDP. Lymph node involvement was not appreciated on plain radiographs or computed tomography (CT).