Non-neoplastic lymphoid infiltrates are relatively common in the head and neck. Lymph nodes can be involved by reactive lymphoid hyperplasia of a wide variety of types, related to infectious and non-infectious causes. The ocular adnexa and the salivary glands are common sites for involvement by IgG4-related disease, an immune-mediated disease often presenting as mass-forming lesions in extranodal sites. ^1,2 Salivary glands can also be affected by cystic lymphoid hyperplasia and lymphoepithelial sialadenitis.³

Infectious mononucleosis, a symptomatic primary infection by Epstein–Barr virus (EBV), frequently causes a florid lymphoid proliferation in tonsils and cervical lymph nodes, often with atypical histologic features potentially mimicking lymphoma.⁴