Esponda v. U.S. Atty Gen., 453 F.3d 1319 (11th Cir. Jun. 28, 2006) (BIA abused its discretion in dismissing appeal based on failure to submit brief without first determining whether the issues were adequately stated in the notice to appeal; whether BIA was correct in summarily dismissing an appeal where no brief was filed is reviewed for abuse of discretion).
http://caselaw.lp.findlaw.com/data2/circs/11th/0513875p.pdf