Most maxillary sinus cysts cause no symptoms at all. They turn up by accident on a scan taken for some other reason.1RSBO. Symptomatic mucous retention cysts of the maxillary sinus: case report The maxillary sinuses are the air spaces behind your cheeks, on either side of the nose. If you just learned you have one, the cyst most likely isn’t why you went for the scan. A cyst that grows large enough to fill much of the sinus can press on the lining and cause pain, pressure, or stuffiness.2PubMed Central. Symptomatic Maxillary Sinus Retention Cyst Following a Prior Sinus Perforation: A Case Report
How Often These Cysts Turn Up Without Symptoms
On MRI scans of people without sinus symptoms, about 1 in 18 (5.7%) had a maxillary sinus cyst.3PubMed Central. A Retrospective Study of the Prevalence of Maxillary Sinus Cysts Incidentally Detected on MRI Among Non-Symptomatic Caucasian Population On CT and dental cone-beam scans, between about 1 in 8 and 1 in 5 people show at least one.4PubMed Central. A Retrospective Study of the Prevalence of Maxillary Sinus Cysts Incidentally Detected on MRI Among Non-Symptomatic Caucasian Population
Dentists spot these regularly, because dental X-rays and cone-beam scans often capture the cheek sinuses. The report may describe a dome-shaped or rounded shadow on the sinus floor.
Your report may call the finding a “retention cyst.” That means a small fluid-filled swelling that forms when a tiny mucus gland in the sinus lining gets blocked.5PubMed Central. Maxillary Sinus Augmentation and Implant Installation in Patients With Pseudocysts and Mucous Retention Cysts Many are actually “pseudocysts,” fluid collected under the lining without a true cyst wall, often linked to dental or other infections.6PubMed Central. Maxillary Sinus Augmentation and Implant Installation in Patients With Pseudocysts and Mucous Retention Cysts Either kind is benign and isn’t a tumor.7RSBO. Symptomatic mucous retention cysts of the maxillary sinus: case report8Hong Kong Journal of Emergency Medicine. Sudden‐onset projectile rhinorrhea from the right nostril
Studies that followed people forward in time found that having a cyst did not match up with having sinus complaints.9Wiley Online Library / International Forum of Allergy & Rhinology. Cysts of the maxillary sinus: a literature review Stuffiness or pain in someone with a small cyst often has another cause. Scans show shape and fluid, not pain, and common sinus or dental problems can cause similar feelings. A doctor matches the cyst’s size and position to the side and type of your symptoms. If you have no cheek pain, stuffiness, or other sinus complaints, the usual next step is to carry on as normal and mention the finding to whoever looks after your sinuses or teeth in the future.
Symptoms a Large Cyst Can Cause
The classic symptom is a dull, steady, non-throbbing ache or pressure under the eye on one side.10PubMed Central. Facial pain as a presenting symptom of a left maxillary sinus cyst: Case report and literature review Some people notice swelling or fullness over the cheek.11PubMed Central. Facial pain as a presenting symptom of a left maxillary sinus cyst: Case report and literature review12PubMed Central. Large dentigerous cyst in the maxillary sinus leading to diplopia and nasal obstruction: case report13PubMed Central. Symptomatic Maxillary Sinus Retention Cyst Following a Prior Sinus Perforation: A Case Report14PubMed Central. Large dentigerous cyst in the maxillary sinus leading to diplopia and nasal obstruction: case report
Large cysts may block the nose, though this is less common.15PubMed Central. Facial pain as a presenting symptom of a left maxillary sinus cyst: Case report and literature review16PubMed Central. Symptomatic Maxillary Sinus Retention Cyst Following a Prior Sinus Perforation: A Case Report Pressure can bring headaches and pain around the eye.17PubMed Central. Symptomatic Maxillary Sinus Retention Cyst Following a Prior Sinus Perforation: A Case Report Some people report tenderness when the cheek is pressed, tingling or numbness, or dizziness.18RSBO. Symptomatic mucous retention cysts of the maxillary sinus: case report
Size matters. Symptoms are mostly linked to cysts that fill the sinus space.19PubMed Central. Symptomatic Maxillary Sinus Retention Cyst Following a Prior Sinus Perforation: A Case Report Surgeons studying symptomatic cysts often look at those filling at least half the sinus.20PubMed. Symptomatic maxillary sinus retention cysts: should they be removed? A small cyst is unlikely to explain strong symptoms.
A sinus infection more often comes with thick yellow or green mucus, fever, a worse sense of smell, or a start soon after a cold. Cyst pressure can hang around for months without any of those infection signs, and that long, quiet pattern is one clue that a structural cause may be involved. Noting which side hurts helps, because a doctor can then check whether it matches the side where the scan shows the cyst. Bring the written scan report and, if you can get them, the images themselves, so the doctor can look at the cyst’s size and position directly.
When a Cyst Blocks the Sinus Drain
Each sinus drains into the nose through a small opening. A cyst sitting at that opening can block it and may lead to infection.21PubMed Central. Symptomatic Maxillary Sinus Retention Cyst Following a Prior Sinus Perforation: A Case Report In one study, nearly 9 in 10 cysts came with a nose or sinus structure difference, such as an extra sinus opening, an unusually shaped middle nasal ridge, or a bent septum.22PubMed Central. Paranasal Sinus Anatomic Variations Accompanying Maxillary Sinus Retention Cysts: A Radiological Analysis Blockage in the drainage area was linked to cysts on the same side.23PubMed Central. Paranasal Sinus Anatomic Variations Accompanying Maxillary Sinus Retention Cysts: A Radiological Analysis
Chronic pain is possible but uncommon. In one reported case, a man in his 30s had ten years of severe one-sided facial pain.24PubMed Central. Severe facial pain and removal of maxillary sinus mucous retention cyst Removing his cyst ended the pain completely.25PubMed Central. Severe facial pain and removal of maxillary sinus mucous retention cyst
For long-lasting facial pain, a doctor rules out other causes first: dental problems in the upper back teeth, ordinary sinusitis, and nerve or jaw pain. A cyst becomes a likely cause only once those are excluded.
Sudden Watery Drip From One Nostril
A cyst can rupture spontaneously and release a sudden, forceful stream of clear watery fluid from one nostril.26Hong Kong Journal of Emergency Medicine. Sudden‐onset projectile rhinorrhea from the right nostril The fluid can be pale yellow or straw-colored rather than perfectly clear. In another case, a cyst burst after a facial injury, causing a one-sided runny nose.27PubMed Central. Ruptured maxillary retention cyst: cause of unilateral rhinorrhea after trauma In one case the person had no further symptoms and needed no surgery.28Hong Kong Journal of Emergency Medicine. Sudden‐onset projectile rhinorrhea from the right nostril
This drip can look like a leak of brain fluid.29Hong Kong Journal of Emergency Medicine. Sudden‐onset projectile rhinorrhea from the right nostril30PubMed Central. Ruptured maxillary retention cyst: cause of unilateral rhinorrhea after trauma The cushioning fluid around the brain can also leak through the nose as a clear watery drip. Doctors may test the fluid for a marker found in brain fluid, or scan to see where it came from. The distinction matters because a brain-fluid leak can carry a risk of infection around the brain, while a burst cyst usually does not.
Seek care quickly if clear one-sided drip follows a head injury. The same goes for drip that keeps going, tastes salty, or worsens when you lean forward. Headache or fever with the drip needs urgent attention. A single gush that stops is more consistent with a burst cyst, though only testing or scanning can confirm the source.
Eye and Vision Symptoms Point to Something Else
A mucocele is a cyst-like lesion that slowly expands its sinus and can thin the bone.31PubMed. Diplopia due to maxillary sinus mucocoele32PubMed Central. Endoscopic sinus surgery for maxillary sinus mucoceles It may rarely push into the eye socket.33PubMed. Diplopia due to maxillary sinus mucocoele34PubMed Central. Endoscopic sinus surgery for maxillary sinus mucoceles When that happens, it can cause double vision, a bulging or drooping eye, watery eye, numbness under the eye, or reduced vision.35PubMed. Diplopia due to maxillary sinus mucocoele Mucoceles are generally treated with surgery, whereas most ordinary cysts are simply left alone.
A dental cyst can do something similar. A large tooth-related cyst growing into the sinus caused double vision, painful cheek swelling, and nasal blockage in one case.36PubMed Central. Large dentigerous cyst in the maxillary sinus leading to diplopia and nasal obstruction: case report Eye or vision symptoms call for a closer look rather than assuming a simple cyst.
Double vision, an eye that seems to bulge or droop, or any loss of vision should be reviewed by a doctor promptly. New numbness of the cheek or upper lip also deserves evaluation, because the nerve running below the eye can be pressed on by an expanding lesion. If you know you have a sinus cyst, mention it when you report these symptoms, since it helps the doctor decide what to scan and who should see you.
Will the Cyst Grow or Go Away
About 3 in 10 cysts shrink over time.37Wiley Online Library / International Forum of Allergy & Rhinology. Cysts of the maxillary sinus: a literature review About half to 6 in 10 stay the same.38Wiley Online Library / International Forum of Allergy & Rhinology. Cysts of the maxillary sinus: a literature review About 1 to 2 in 10 grow.39Wiley Online Library / International Forum of Allergy & Rhinology. Cysts of the maxillary sinus: a literature review Most people need no further tests or treatment.40Hong Kong Journal of Emergency Medicine. Sudden‐onset projectile rhinorrhea from the right nostril Cysts that shrink may do so after an infection settles, which fits with the idea that some are pseudocysts linked to infection.
The main reason to scan again is new or worsening symptoms, such as growing cheek pressure, blockage, or any eye change. For a cyst with no symptoms, repeat scanning on a schedule is usually not needed. An ear, nose and throat specialist (ENT) decides whether to follow a cyst, based on its size and on what you are feeling. If you are planning a dental implant or a sinus lift, the cyst may need to be assessed first, because that procedure works in the same area of the sinus floor.
When Treatment Helps
Cysts without symptoms need no treatment.41PubMed Central. Severe facial pain and removal of maxillary sinus mucous retention cyst Surgery is recommended only for pain or blockage, including in children.42Pediatric ENT of Oklahoma. Does My Child Need Sinus Surgery? Before surgery, scans such as CT help separate cysts from polyps or tumors.43Michael Bublik Site. Maxillary Sinus Retention Cyst Treatment Los Angeles | SCENTAA
When surgery is done for symptoms, it often works. About 9 in 10 people (88%) felt much better after endoscopic surgery.44PubMed Central. Surgical outcomes between two endoscopic approaches for maxillary cysts Headaches, facial pain and pressure, drip, and blockage all eased.45PubMed Central. Surgical outcomes between two endoscopic approaches for maxillary cysts
The surgeon works through the nostril with a thin camera and small instruments, so there are usually no cuts on the face. The aim is generally to open the sinus and remove or drain the cyst so that the sinus can drain normally. Recovery often takes days to a couple of weeks, and the nose may feel blocked or crusty in that time. It is reasonable to ask the surgeon about the risks and about the chance that symptoms will persist.