Retention cysts of paranasal sinuses are benign lesions usually discovered incidentally on a plain sinus radiograph or cross-sectional imaging of the head. They do not usually cause symptoms.
They are also referred to as mucous retention cysts.
It is difficult to estimate their true incidence since most studies report findings of retention cysts on imaging performed for unrelated symptoms. However, an incidence of 29 -31% has been reported on studies on adults undergoing brain MRI 3,4.
Although usually discovered incidentally, retention cysts can cause headache, peri-orbital pain and nasal obstruction. They may occasional present with repeated episodes of sinusitis.
They are slow growing lesions, but mucosal and cortical integrity is preserved.
On radiographs, they are radiopaque, dome-shaped structures with a rounded edge, located on the floor of the maxillary sinus.
Similar to radiographs, retention cysts are seen on CT/MRI as rounded dome-shaped lesions usually situated on the maxillary sinus floor. They are of low attenuation on CT where they cannot be differentiated from a small polyp.
On MRI they are usually T1 and T2 hyperintense as opposed to polyps that tend to be of low T1 signal.
Treatment and management
Mostly no treatment is indicated, because of their high spontaneous regression rate 1,2. If symptomatic or causing nasal obstruction they can be surgically resected endoscopically.
- 1. Wang JH, Jang YJ, Lee BJ. Natural course of retention cysts of the maxillary sinus: long-term follow-up results. Laryngoscope. 2007;117 (2): 341-4. Laryngoscope (full text) - doi:10.1097/01.mlg.0000250777.52882.7a - Pubmed citation
- 2. Donizeth-Rodrigues C, Fonseca-Da Silveira M, GonçAlves-De Alencar AH et-al. Three-dimensional images contribute to the diagnosis of mucous retention cyst in maxillary sinus. Med Oral Patol Oral Cir Bucal.;18 (1): e151-7. Free text at pubmed - Pubmed citation
- 3. Hansen AG, Helvik AS, Nordgård S, Bugten V, Stovner LJ, Håberg AK, Gårseth M, Eggesbø HB. Incidental findings in MRI of the paranasal sinuses in adults: a population-based study (HUNT MRI). BMC ear, nose, and throat disorders. 14 (1): 13. doi:10.1186/1472-6815-14-13 - Pubmed
- 4. Bal M, Berkiten G, Uyanık E. Mucous retention cysts of the paranasal sinuses. Hippokratia. 18 (4): 379. Pubmed