The ranula is a mucous extravasation phenomenon (mucocele) that occurs in the floor of the mouth. Disruption of the duct of either a sublingual gland or minor salivary gland results in mucous spillage.

Ranulas generally occur in the first two decades of life, with no particular sex predilection. They present as unilateral, bluish, dome-shaped, non-tender, fluctuant swellings in the floor of the mouth, although deeper lesions may be normal in color. Ranulas may reach several centimeters in diameter, filling the floor of the mouth and elevating the tongue.

Spilled mucin may dissect below the mylohyoid muscle and produce a swelling in the neck. This is referred to as the "plunging" or "cervical" ranula.

They may develop rapidly and be present for a few days with gradual increase in size.

Related topic: Oral mucocele