Many people first notice a ranula when the tongue feels pushed up or speech sounds slightly different, then find a soft, bluish swelling on the floor of the mouth. It is not a tumour and it is rarely painful. It is a pool of saliva that has leaked from one of the small glands under the tongue, and the main challenge is stopping it from filling up again.
Saliva leaking from the sublingual gland
You have two sublingual salivary glands, one on each side under the tongue. If a gland or its tiny ducts are damaged, for example by a knock, a bite or minor surgery nearby, saliva can escape into the surrounding tissue instead of draining into the mouth. The body walls it off, and a dome of fluid builds up. Because the swelling has no true lining of its own, it is described as a pseudocyst rather than a true cyst. Often no clear cause is found.
The name comes from the Latin for a small frog, after the resemblance of a large swelling to a frog's throat pouch.
Two forms: in the mouth and in the neck
An oral ranula stays above the floor-of-mouth muscle and is visible as a soft, translucent or bluish lump beside the underside of the tongue. A plunging ranula extends through or around that muscle into the neck, where it shows up as a soft swelling under the jaw, sometimes with little to see inside the mouth. A 2025 systematic review in the Journal of Laryngology and Otology (Lazzeroni and colleagues) proposed grouping ranulas by how far they extend: within the mouth, into the neck, or deeper into the space beside the throat.
A ranula is a different thing from a mucocele on the lip, which comes from one of the many tiny minor salivary glands and often settles by itself. Our article on mucoceles and lip cysts explains those. Sublingual glands keep producing saliva steadily, which is one reason ranulas tend to persist.
How it is diagnosed
An oral ranula is often recognisable from its look and feel. A dentist will also consider other causes of swelling in the floor of the mouth, such as a blocked submandibular duct or salivary stone, a dermoid cyst, an infection or, rarely, a growth. A plunging ranula, or any swelling in the neck, usually needs imaging such as ultrasound or MRI to show its extent before treatment is planned.
Any lump, ulcer or patch in the mouth that has not healed or changed within three weeks should be checked by a dentist or GP. Our guide to white and red patches in the mouth explains why changes like these are always worth a look.
Treatment choices, and what the evidence says about recurrence
Ranulas are treated by an oral and maxillofacial surgeon or an ear, nose and throat surgeon. The main approaches are:
| Approach | What it involves | Points to weigh |
|---|---|---|
| Removing the sublingual gland | The leaking gland is removed, with or without the pseudocyst wall | Treats the source of the saliva; a larger procedure near the lingual nerve and the submandibular duct |
| Marsupialisation, sometimes with packing | The top of the swelling is opened and stitched so it drains into the mouth | Smaller procedure; the gland stays, so the swelling can return |
| Micro-marsupialisation | Stitches are passed through the swelling to create new drainage channels | The least invasive option; the gland stays, so the swelling can return |
| Removing the swelling only | The pseudocyst is cut out but the gland is left | The gland can keep leaking |
The two most recent reviews are worth reading together. The 2025 review by Lazzeroni and colleagues pooled 42 studies and found that removing the sublingual gland had the highest success rates, and the authors described it as the standard of care. A network meta-analysis published the same year in the Journal of Oral Pathology and Medicine (Souza and colleagues) compared seven treatments across 18 non-randomised studies and concluded that, because the certainty of the evidence was low to very low, no single treatment could be shown to be clearly superior.
In practice, the logic that removing the leaking gland deals with the source carries a lot of weight with surgeons, while less invasive methods remain reasonable first steps for some people. Your surgeon will explain the trade-offs for your situation, including the size and extent of the ranula and the risks of each option.
Recovery after surgery
Sublingual gland removal is commonly done under general anaesthetic, although smaller procedures may be done under local anaesthetic. Expect some swelling and soreness under the tongue for several days, a soft diet for a short time, and careful, gentle cleaning of the area. Because the lingual nerve runs nearby, temporary numbness or altered sensation of the tongue is one of the risks your surgeon will discuss. Losing one sublingual gland does not usually cause a noticeably dry mouth, as the larger salivary glands produce most of your saliva.
Common questions
Can I pop or drain it myself?
No. It may shrink briefly, but the gland keeps producing saliva and the swelling usually refills. Puncturing it at home also risks infection.
Is a ranula cancer?
No. A ranula is a benign collection of saliva. Other lumps can look similar, though, which is why an examination is important.
Why has mine come back?
Recurrence is more likely when the sublingual gland is left in place, because it can keep leaking. If a ranula returns after a smaller procedure, gland removal is often discussed as the next step.
If you have noticed a soft swelling under your tongue or a new lump under the jaw, a dentist at Lumi Dental in Melrose Park can examine it and, where needed, arrange referral to a surgeon. You can book through our general dentistry page or see our current offers.
