Sialocele
A sialocele is a localized, subcutaneous cavity containing saliva. It is caused by trauma (e.g. violence, accident or surgery) or infection. They most commonly develop about 8-14 days after injury.
They are a relatively common complication following surgery to the salivary glands, commonly parotidectomy (removal of the parotid gland). In this case the sialocele is the result of saliva draining out of remaining parotid tissue, and occurs about 5 to 10% of cases of superficial (parital) parotidectomy.