Which of these pathologies is the most common benign tumour of the parotid gland?

Mumps causes the classic bilateral parotitis, but it can present as a unilateral enlargement in rare cases. Heerfordt syndrome includes sarcoidosis. Tuberculosis historically was associated with ‘cold abscess’. It is caused by Mycobacterium tuberculosis, an acid-fast bacterium that does not stain with Gram stain. It requires Ziehl–Neelsen staining.