Case 32 Answer

Answer: Dupuytren’s contracture (aka palmar fibromatosis)

This is a tough one because you don’t actually see the disease process. You see the sequela, ie the persistently flexed 4th digit on all images. If I gave the history of trauma, sure it could be an extensor tendon injury, but without trauma, think palmar fibromatosis - ie the palpable nodules on the palmar aspect of the hand. As the fascia fibrosis down, it can lead to progressive flexion of the digits (classically the 4th digit!)

reference (short and sweet): https://radiopaedia.org/articles/dupuytren-contracture

ref (grab a cup of coffee): https://pubs.rsna.org/doi/full/10.1148/rg.297095138