Kimura's Disease in an Elderly Male: A Case Report of Unilateral Painless Submandibular Mass With IgG4-Positive Plasmacytosis.

This report describes an atypical presentation of Kimura's disease (KD) in a 73 year-old male with painless left mandibular masses, localized swelling, and pruritus. Distinct from classic KD manifestations, the patient was an elderly male exhibited no significant serum eosinophilia, while imaging demonstrated inflammatory changes in the submandibular tissues and cervical lymph nodes. Histopathologic and immunohistochemical analyses confirmed KD with IgG4-positive plasmacytosis. This case highlights the importance of considering KD in the differential diagnosis of head and neck tumors, particularly in elderly patients lacking classic biomarkers. Notably, the marked infiltration of IgG4-positive plasma cells in the affected tissue further suggests a potential overlap between KD and IgG4-related disease mechanisms. These findings emphasize the relevance of incorporating atypical cases in the current body of knowledge.