A man who reported to hospital with a sore knee walked out and never came back after doctors told him his penis was turning to bone.
The bizarre case is detailed in the latest issue of journal Urology Case Reports,published online at the end of last week.
The 63-year-old had suffered a fall, hurting his buttocks and knee. He went to hospital, where doctors did an X-ray to see if there were any fractures. There weren't, but he told them he was also suffering pain in his privates.
The X-ray showed he had an "extensive plaque-like calcification along the expected distribution of the penis", and diagnosed him with penile ossification.
Essentially, calcium salts had built up in the soft tissue, turning it hard.
"Penile ossification refers to the process by which calcium salts build up in soft tissue, forming extraskeletal bone," the report read, noting that it's extremely rare - with fewer than 40 reported cases in history.
The patient had a history of alcoholism, but doctors couldn't say if that was the cause because he left "against medical advice", and no investigation or follow-up could be done.
They suspect he has Peyronie's disease, which "reduces flexibility and leads to a penile bend or curvature during erection, leading eventually to erectile dysfunction".
The man's town or the hospital he showed up at were not mentioned.