Paranasal sinus mucocoeles represent complete opacification of
one or more paranasal sinuses by mucous, often associated with
bony expansion. Clinical presentation depends on two factors: -
location and direction of expansion - presence of infection
Mucocoeles distort local anatomy and exert pressure on adjacent
structures as they enlarge. Examples include: - frontal
mucocoele extending into the front of the orbit, presenting as a
mass - posterior ethmoidal mucocoele compressing the orbital
apex - sphenoidal mucocoele extending posteriorly impinging upon
the pituitary and brainstem - maxillary mucocoele may elevate
the orbital floor and result in proptosis If a mucocoele becomes
infected presentation is similar to acute sinusitis, with
potential extension of infection into adjacent spaces: -
intracranial - subdural empyema, meningitis, cerebral abscess -
orbit - subperiosteal abscess - subcutaneous - e.g. Pott's puffy
tumour Mucoceles most likely occur as a result of obstruction of
the ostium of a sinus with