Ranula, which is mucocele originated from greater and lesser salivary glands of the oral floor region, presents unilateral swelling of this region as main symptom, but occasionally extends beyond mylophyoid muscle to the mental and submandibular parts of the oral region, where its swelling is developed. Although it is called plunging ranula in view of its site of onset, it rarely developes primarily from the submandibular part.
We report here a personal case of plunging ranula developed primarily in the above part of a 3-year-old girl, together with some additional considerations.
1) During the past 20 years in this country, as far as infants aged below 5 years are concerned, only 4 cases were reported to have presented primary symptoms of ranula in the submandibular part.
2) The involvement of the age in the pathogenesis of plunging ranula seemed to be undeniable.
3) The aminoacid analysis of the protein in the intracystic fluid seemed to leave room for further examination.
4) Good results were obtained by both extirpation of sublingual gland and cystectomy. Some additional considerations were made from the angles of this experience of ours and the literature.
