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.

Kikuchi-Fujimoto disease, a rare form of necrotizing lymphadenitis, is an uncommon, benign, self-limiting disorder of obscure etiology. It affects mostly young adults of both genders. Clinically, it presents with fever and lymphadenopathy of a firm to rubbery consistency frequently involving cervical lymph nodes while weight loss, splenomegaly, leucopenia, and elevated erythrocyte sedimentation rate feature in severely affected patients. Cutaneous involvement occurs in about 30%-40% of cases as facial erythema and nonspecific erythematous papules, plaques, acneiform or morbilliform lesions of great histologic heterogeneity. Both Kikuchi-Fujimoto disease and systemic lupus erythematosus share an obscure and complex relationship as systemic lupus erythematosus may occasionally precede, develop subsequently, or sometimes be associated concurrently with Kikuchi-Fujimoto disease. It is often mistaken for non-Hodgkin lymphoma while lupus lymphadenitis, cat-scratch disease, Sweet's syndrome, Still's disease, drug eruptions, infectious mononucleosis, and viral or tubercular lymphadenitis are other common differentials. Fine needle aspiration cytology mostly has features of nonspecific reactive lymphadenitis and immunohistochemistry studies usually show variable features of uncertain diagnostic value. Since its diagnosis is exclusively from histopathology, it needs to be evaluated more carefully; an early lymph node biopsy will obviate the need for unnecessary investigations and therapeutic trials. Its treatment with systemic corticosteroids, hydroxychloroquine, or antimicrobial agents mostly remains empirical. The article reviews clinicoepidemiological, diagnostic, and management aspects of KFD from the perspective of practicing clinicians.