This is one of the few obscure named diseases that I actually already knew about when I came across it in my studies. It is a nodular fibroblastic proliferation of palmar fascia, which leads to contracture of (most commonly) the fourth and fifth digits. It typically affects older men of Northern European heritage, can be hereditary, and has also been associated with chronic liver failure. Not too much more is known about the pathophysiology at this time, but there may be an association with certain genes (MafB), and myofibroblasts play a role in this disease. Treatment is surgical (fairly simple), but recurrence is common.

Basically, the patient will come to you because their ring and pinky fingers are curled and can't be fully extended. You can feel nodules in the palm and can often feel cords in the fingers. It is more common than I thought (saw quite a few cases on my hand surgery rotation). I also saw it a lot when I rotated through the Veterans Health Administration, which makes a lot of sense.