The lingual mandibular bone concavity is not pathognomonic but is a radiographic bone entity. The origin of the entity and the histologic picture of the contents found within the concavity are probably related to the size and growth of the structures located in the submandibular space and the contiguous area. This accounted for the presence of normal submandibular space tissue contents in this patient and in nine of the ten patients whose conditions are reviewed in the literature. The question of whether a surgical exploration is indicated should be decided in terms of each individual case by the oral surgeon. However, only by performing a surgical exploration and submitting the tissue contents for a histopathologic examination can an accurate diagnosis be made. The general practitioner of dentistry should be aware of this bone entity and be prepared to discuss the condition with the patient and to refer the patient for exploration of the area if appropriate.