5 year old who fell off a slide.

Initial imaging shows a comminuted fracture through the distal humerus, compatible with a supracondylar fracture. Nothing else appreciable here, except maybe in retrospect some lucency of the distal humerus where the fracture is.

4- and 7-month follow-up radiographs shows a growing lucent lesion of the distal humerus, expanding the bone there. It has a multicystic appearance. A diagnosis of large simple bone cyst versus aneurysmal bone cyst was proposed.

12 month follow-up was done after the cyst was opened surgically, its contents scraped off, and the resulting cavity was packed with allograft bone chips. At surgery, this turned out to be an aneurysmal bone cyst.

5 year follow-up shows involution of the cyst cavity with some residual heterogeneity and a bone spur at the anterior aspect of the distal humerus.

    • @SpectatorOPMEnglish
      9•1 year ago

      Yes, cysts can form in bone.

      However, this particular entity, aneurysmal bone cyst, is the name of an actual tumor that happens to produce a lot of cysts.

      You can see the other case I posted today for what an ABC looks like on MRI - I think you see why it’s called an aneurysmal bone cyst. Unfortunately, that appearance is not specific for ABC. That other case did turn out to be cancer.