Can a maxillary sinus retention cyst be cancerous?

Posted by kewp @kewp, Jun 23, 2022

RE: Maxillary mucous retention cyst. My panoramic dental X-ray shows Lt Maxillary sinus half-size of the Rt due to some growth on the lateral side of Lt Max sinus, top to bottom. ENT Dr says it is mucous retention cyst & not treatable & was quite dismissive. My question is, due to lateral location & large size half of sinus & being unilateral, would a CT scan be in order to rule out any other diagnosis, such as cancer?

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@kewp, eventhough malignant tumours of maxillary sinus are rare, I can understand your wanting to be sure about the diagnosis.

Maxillary sinus retention cysts are relatively common, many people don’t know they have them. In most cases, these cysts have no symptoms and are only discovered in an imaging exam. Did you only find out you had the cyst because of the dental imaging being done for other reasons? Did you ask the ENT specialist if further imaging might rule out cancer?


Yes, my DDS was concerned because it became larger since last panoramic X-ray. I didn’t think to ask my ENT about a CT scan, because he was rather dismissive about the whole thing & seemed irritated at my question of any treatment. He went on to clean wax from my ears. I could ask my general Dr. I’m concerned that the growth takes up so much space, leaving only half the sinus clear. And seems to be entire lateral edge, rather than from floor of sinus as I’ve seen online. But then I can’t read X-rays! I do have long Hx of migraine h/a & chronic vasomotor rhinitis, very bad colds with total nasal congestion & when it starts draining, there is so much more on Left, I have to blow & blow tho I know you’re supposed to suck it in! (ENT said all that mucus comes from nasal membranes, not retention cyst, another irritating question I asked).
(I was actually at Mayo in 1981 with my 1st ITP episode where I complained of my “bad sinus colds”, was taking Sudafed. I went for opinion on splenectomy, but miraculously, my platelet count came up on that very day of visit, after being on high-dose steroid. Mayo Heme said not to takeOTC cold Rx & see if 10 years I’m ok, then can take. I did! But relapse after 19 yrs & 2 more).

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