Benign Lymphoepithelial Lesion (Parotid Cyst)

22-year-old female presented for recurrent right-sided facial swelling and pain. There is a well circumscribed, T1-hypointense, T2-hyperintense, non-diffusion restricting cystic lesion involving the superficial and deep lobes of the right parotid gland. The lesion has a thin, barely perceptible wall. No suspicious enhancement. It effaces the retromandibular vein on the right. The findings are compatible with a benign lymphoepithelial lesion (BLL). BLL can be seen in the setting of HIV. Lesions may be bilateral in up to 20%, and are thought to be secondary to duct dilatation from obstruction due to lymphoid hypertrophy. Differential diagnosis includes Warthin’s tumor, first branchial cleft cyst, sialocele and cystic intraparotid nodal enlargement.