Penis growth in adulthood

No.12950506 ViewReplyOriginalReport
https://www.jsm.jsexmed.org/article/S1743-6095(15)31114-0/fulltext
Quick rundown:
>33 year old male had a 9 year history of priapism (erections that do not go away by themselves)
>This eventually lead to extreme enlargening of his penis
>His penis' circumference had increased to 21cm (!)
>His corpora cavernosa had increased massively in size

The question is, how does priapism result in the permanent enlargement of the penis? Keep in mind, he was still able to get erections.

Discuss