A 2.2 x 1.3 x 2.6 cm enhancing soft tissue mass is observed along the dorsolateral aspect of the right first metacarpal, consistent with residual or recurrent tumor, as the patient reports history of osteosarcoma status post chemotherapy.
The mass envelops the extensor pollicis longus and extensor pollicis brevis tendons, without definite invasion of the underlying metacarpal; however, an abnormal low T1 high STIR signal is seen within the 1st metacarpal diaphysis, which likely represnts osteosarcoma with in the bone, but also has a double line appearance suggestive of bone infarction. If infarction, it is likely secondary to prior radiation therapy in the region.