A study by Bagán et al. (1), considering 25 mucoceles
suffered in the general population, showed that 5% were
retention mucoceles whereas the other 95% were extravasation.
They proposed that extravasation mucoceles
undergo three evolutionary phases. In the first phase,
mucous spills diffusely from the excretory duct into conjunctive
tissues where some leucocytes and histiocytes
are found. Granulomas appear during the resorption
phase due to histocytes, macrophages and giant multinucleated
cells associated with a foreign body reaction.
In the final phase connective cells form a pseudocapsule
without epithelium around the mucosa.