Sorry buddy, but you are NOT 10% BF. You might be 10% body HAIR, but not body fat. You look well into the 30s, I'd say. Hell, even I'm about 18% and I can see striations in my quads. A lot of "lean" guys are like 10%. Don't underestimate.
Don't worry about all the jokes. It's just that with all the steroids/supplements questions and whatnot it just seems pretty ridiculous.
You need to cut....badly. You won't gain new muscle while on a cut, unelss (a) you're a beginner, (b) you're a genetic freak, and/or (c) you're using performance-enhancing drugs. It's possible to see performance gains. However, muscle gains are out of the question.
You want to keep the volume low and the intensity high, while on a calorie deficit. Aim for key compound lifts like squats, deads, presses, cleans, etc. You need to reinforce your body's need for that "mass" while in nitrogen imbalance (i.e. catabolic state). No offense, but you can probably get away with some extra cardio to help get over that first (metaphorical) hurdle. From there, you'll need to be all that more strategic in your diet and training.
Diet = weight loss. Remember that. Restric your carbs, but always incorporate refeeds every 2-5 days (depending on your BF and degree of calorie deficit) to keep your leptin levels moderated.
Read the stickies in the diet and nutrition section for more info.