Does anyone know why I have a brown discharge 10 days before my period should start?

The discharge could come during the time you're ovulating. Here's a website on female health that might help you:

Vaginal Discharge (http://www.pamf.org/teen/health/femalehealth/discharge.html)

Does anyone know why i have a brown discharge 10 days before my period should start?
Are you on birth control? Some birth control pills or even the shot afect the hormone levels and could cause it . You should go to your obgyn just in case.