What is the most common soft-tissue sarcoma in paediatric patients?
Rhabdomyosarcoma, accounting for over 50% of cases.
Which rhabdomyosarcoma subtype has the worst prognosis?
The alveolar subtype.
There's an infiltrating soft tissue mass, spanning the length of the 1st to 3rd metatarsal bones, involving the muscles and tendons of the dorsum of the foot in this location as well as the interossei muscles in the 1st and 2nd web spaces. The lesion encases the 2nd metatarsal bone and is adjacent to the 1st and 3rd metatarsal bone, with no evidence of bony destruction. It is isointense on T1W1, hyperintense on T2WI, with slightly heterogeneous contrast enhancement. A small cystic area is visible superficially to the 2nd metatarsal shaft, which may correspond to an area of necrosis or a fluid collection.