Kikuchi-Fujimoto Disease With Isolated Mediastinal Lymphadenopathy: A Rare Presentation of an Even Rarer Disease.

Kikuchi-Fujimoto disease (KFD) is a rare self-limiting condition presenting as fever and cervical lymphadenopathy, with only two reported cases with isolated mediastinal lymphadenopathy. Lack of awareness about this condition often results in a high rate of misdiagnosis. We present a case of a 29-year-old Indian male with fever, mucocutaneous ulcers, weight loss, and mediastinal lymphadenopathy on CT. Extensive investigations ruled out malignancy and autoimmune and infectious causes. Endobronchial ultrasound-guided fine needle aspiration revealed necrotizing lymphadenitis, indicating KFD, followed by symptomatic management and reassurance. Awareness is crucial to avoid misdiagnosis and unnecessary treatment due to its potentially serious differentials. Long-term follow-up is imperative due to its association with autoimmune conditions.