Aspiration cytology of pleomorphic adenoma with squamous metaplasia: A case series and literature review illustrating diagnostic challenges.

Squamous metaplasia in PAs is not associated with adverse outcomes, but may induce reactive changes upon aspiration/irritation, resulting in worrisome cytologic features. PLAG1 IHC is a useful adjunct when characteristic cytologic features for PAs are absent or obscured. Prudent use of the diagnostic category salivary gland neoplasm of uncertain malignant potential (SUMP) in the Milan system can avoid overtreatment.