Encysted parasitic larvae in the mouth.

Oral appearances of intestinal parasitic disease are rare. One such appearance is the presence in oral tissues of encysted or encapsulated larvae of organisms from the classes Cestoidea and Nematoda. Cestode larvae form cyst-like lesions that are often clinically diagnosed as mucoceles. In these lesions, the cyst cavity is lined by fibrous tissue with inflammatory cells, and contains fluid and the larval stage of a parasite. The diagnosis of these parasitic cysts is more frequently made in younger persons. The cysts may be treated by simple excision, but care must be taken that the cyst does not rupture, as in some parasites this may result in new cyst formation. Nematode infection in the oral cavity, the most common of which appears to be trichinosis, is rarely reported. Patients with oral or maxillofacial (or both) parasitic disease must undergo a thorough medical investigation to exclude possible life-threatening involvement in other parts of the body.