12 year old female status post 5 cycles of chemotherapy, history of osteosarcoma Enhancing, T2 intense lesion of the distal femoral diaphysis measures 15.3 cm in craniocaudad dimension and 4.7 x 3.8 cm in transverse and AP dimensions. There is associated cortical thinning and periosteal reaction with an enhancing soft tissue mass extending medially through the cortex. Overall the dimensions are not significantly changed from the prior exam although there is less intense contrast enhancement and decreased periosteal reaction. Enhancement and T2 signal abnormality extending along the medial soft tissues to the skin surface presumably represents seeding of the biopsy tract and is new from the prior exam. No skip lesions are identified.
Left femoral osteosarcoma with persistent enhancement and new presumed seeding of the biopsy tract.