<unk> , micrograph. H&E stain. The histologic appearance is similar to mucoceles from other locations. The spilled mucin causes a<unk> tion tissue to form, which usually contains foamy histiocytes. Ultrasound and magnetic resonance imaging may be useful to image the lesion. A small squamous cell carcinoma obstructing the Wharton duct may require clinical examination to be distinguished from a<unk> . Criteria * Mostly seen in young children and adolescents, both sexes are equally affected. Swelling in floor of mouth, which may be painful. Mostly unilateral, on one side of frenulum. * Shape is spherical * Size varies from 1 – 5 cm in diameter * Color is pale blue with characteristics semi transparent appearance. * Surface is smooth and mucous membrane is mobile over the swelling. * Tenderness is absent * Fluctuation test is positive * Transillumination test is positive * Cervical lymph nodes are not enlarged. * May or may not have prolongation in the neck. Classification A<unk>  is a type of mucocele, and therefore could be classified as a disorder of the salivary glands. Usually a<unk>  is confined to the floor of the mouth (termed a "simple<unk> "). An unusual variant is the cervical<unk>  (also called a plunging or diving<unk> , where the swelling is in the neck rather than the floor of the mouth. The term<unk>  is also sometimes used to refer to other similar swellings of the floor of mouth such as true salivary duct cysts, dermoid cysts and cystic hygromas. The Latin word rana means "frog"<unk>  = "little frog").
Ranula
Microgyrus
Ateronon
Syrinx 
Stenopaeic slit
Pinguecula
Otic pit
Orbital septum