The Stafne defect is thought to be caused by an ectopic portion of the submandibular salivary gland which causes the bone of the lingual cortical plate to remodel. Rarely, the defect can be completely surrounded by bone, and this has been theorized to be the result of entrapment of embryonic salivary gland tissue within the bone. Similar, but rarer, defects may be present in the anterior portion of the lingual surface of the mandible.