A recent case in Philadelphia leads to the question: Why would people allow an untrained medical professional to perform plastic surgery on them, and why do these cases sometimes result in death? Chris Tzarnas, chief of plastic surgery at Temple, said silicone can travel through the bloodstream if the needle hit a vein instead of just the fatty tissue in the buttocks. "If it's injected into a very large vein, it's going to end up in the heart and or the lung vasculature," Tzarnas said. "Then it lodges there and blocks the normal blood flow, which could be potentially catastrophic."