Female 32 years chance finding of two asymptomatic dome shaped well defined opacities attached to the floor and outer wall of the right maxillary sinus.
Although I have presented once before a patient with a pseudocyst, these two are such good examples that it is worth while seeing them.
Just to remind you, a pseudocyst is a fluid filled sac of mucosa which is not epithelial lined (definition of a true cyst). It is believed they are caused by a blockage of the duct from a mucous gland in the mucosa and the pressure of the fluid causes a dissection of the mucosa allowing a spherical ball to form.
These are usually asymptomatic and spontaneously burst so no treatment is required.