What Causes Internal Cartilage Build Up Along With Clear Liquid Discharge?

I have an internal cartilage build up that feels like a tube and discharges a clear liquid and sometimes blood. at the surface sometimes a blister is formed and it becomes sore and then ultimately pops and dries up again. I saw a doctor a while back and he said it was harmless but could be removed if it bothered me and that likely it came from sitting down on a desk chair for long periods. Any idea specifically what this is and how I should handle ?