The mysterious case which stumped an experienced ENT surgeon

A surgeon with more than 50 years on the job is baffled by this presentation. What could the diagnosis be?

A previously healthy 48-year-old married lawyer with two teenage children presents with a swelling under the angle of her right mandible.

woman sore throat neck
The patient had 13 more episodes of salivary gland swelling.

The swelling occurred near the end of a six-hour plane trip. She is otherwise well, with no systemic symptoms of note.

She is a vegetarian who neither drinks alcohol nor smokes. There is