Scanning electron microscope showed a peculiar structure made from calcium apatite crystals and whitlockite - an unusual form of calcium phosphate - which clearly pointed to the prostate as the stones' origin.
In addition, the researchers found bacterial imprints within the stones. This could indicate that active inflammation was present in the individual during his life.
The tall men and women who made up the pre-Mesolithic population of Al Khiday were rather healthy. Anthropological investigation revealed they did not suffer from chronic disease, apart from bad teeth, which was revealed by a high frequency of cavities found among the dental remains.
Overall, no significant disease, apart from the prostate stones, was found.
Demonstrating that prostate stones did exist more than 10,000 years ago is an extraordinary finding, according to bioarchaeologist Michaela Binder, a research associate at the Austrian Archaeological Institute in Vienna who is not involved in the study.
"Finding such a disease in association with a skeleton from an archaeological site opens a new window into health and living conditions in the past," Binder told Seeker.
Although it might be difficult to reconstruct how people in the past would have experienced or perceived pain, it's likely that the prehistoric man spent his last days in excruciating pain.
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Prostate stones are usually very small, asymptomatic and rather common in adults. But the large size of those found in the burial suggests a mechanical obstruction to the urinary tract. This would have made the man's life miserable.
"In modern clinical cases there is often lower back pain or leg pain, difficulties and pain when urinating. Given the size of the stones obstruction of the urinary tractus would have certainly been a problem and in times very uncomfortable and painful," Binder said.
According to the researchers, the localized symptoms may have advanced to more systemic ones, "causing pelvic dilatation, cystitis, renal scarring and kidney failure, potentially leading to the death of the affected individual," they wrote.
The prostate stones are the oldest found so far in the archaeological record. Previously, an 8,500-year-old bladder stone was found in the pelvis of an adult female buried in cave-tomb on the coast of Sicily.
"Our finding confirms this disease can no longer be considered a disease of the modern era. It also affected prehistoric people, whose lifestyle and diet were significantly different from ours," Usai said.
Top photo credit: Centro Studi Sudanesi e Sub-Sahariani - Treviso/Università di Padova