A branched cellular projection (or cytoplasmic extension) that is extended from the surface of a dendritic immune cell, and which enables the cell to sample luminal pathogens and increase the surface area for antigen presentation to T cells. [ http://www.ncbi.nlm.nih.gov/pubmed/12200351 GOC:BHF http://purl.obolibrary.org/obo/CL_0000451 GOC:cjm ]