It happened after heart surgery. Visited my urologist, he told me often happens after heart surgery where they put you on heart/lung machine, something no one tells you is a side effect up front. Not a major curve, mostly painful getting it up but that all went away after a few months. The result dick is different, lost length (which was the main feature) and gained girth.
Apparently plaque builds up in tissue so when blood flows in it gets blocked in these areas causing a curve.