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.

Doctors at Prince of Wales Hospital in Hong Kong were at a loss after examining an 84-year-old man admitted for complications relating to an enlarged prostate. But medical experts weren’t perplexed by his prostate issues—they were surprised at the patient’s unnaturally silver skin, fingernails, and even whites of his eyes.