He tested positive for Drostanolone and Androstane after his fight against Nick Diaz at UFC 183 .
Silva , the Brazilian mixed martial artist and former UFC Middleweight Champion , holds the longest title defense streak in UFC history .
Silva tested positive for Drostanolone and Androstane after Silva 's fight against Nick Diaz at UFC 183 .
Silva , the Brazilian mixed martial artist and former UFC Middleweight Champion , holds the longest title defense streak in UFC history .