When an 84-year-old man in Hong Kong was admitted to a hospital for a condition related to an enlarged prostate, doctors noticed something else about him—he was oddly gray, according to a case report in the New England Journal of Medicine.
His skin, particularly his face, had an ashen appearance. His fingernails and the whites of his eyes had become silvery. When doctors took a skin biopsy, they could see tiny, dark granules sitting in the fibers of his skin, in his blood vessels, in the membranes of his sweat glands, and in his hair follicles.
A blood test made clear what the problem was: the concentration of silver in his serum was 423 nmol/L, over 40 times the reference level for a normal result, which is less than 10 nmol/L. The man was diagnosed with a rare case of generalized argyria, a buildup of silver in the body's tissue that causes a blueish-gray discoloration—which is generally permanent.