Palpable mass on the left ankle in a patient with history of metastatic melanoma. Corresponding to the FDG positive lesion seen on prior PET/CT, there is a approximately 1.2 x 2.1 predominantly rim/heterogeneously enhancing lesion just posterior to the distal tibial metaphysis. There is displacement, but no frank invasion between the mass and underlying vascular/ligamentous structures.There is focal subcentimeter enhancement within the marrow of the distal fibula and tibia with mild enhancement of uncertain significance.
1. Although radiographic findings of soft tissue tumors are relatively nonspecific, within the context of this patient's history and previous PET/CT, the enhancing lesion just posterior to the distal tibial metaphysis is concerning for metastatic involvement. There is displacement but no frank invasion of underlying structures.2. Focal subcentimeter enhancement within the marrow of the distal fibula and tibia is of uncertain significance but may be representative of further metastatic involvement.