An uncommon presentation of Kikuchi-Fujimoto disease as mediastinal lymphadenopathy.

We experienced an uncommon presentation of Kikuchi-Fujimoto disease (KFD) with sole mediastinal lymphadenopathy in senior age, which was histologically diagnosed by thoracoscopic biopsy leading to appropriate therapy. A 69-year-old man was admitted due to intermittent high fever, general malaise, and appetite loss lasting over 3 months along with 10-kg weight loss in 6 months. Chest computed tomography (CT) showed isolated mediastinal lymphadenopathy, and malignant diseases including malignant lymphoma or metastatic carcinoma, tuberculous lymphadenitis, and sarcoidosis were considered. Therefore thoracoscopic biopsy should be performed for the correct diagnosis, even in uncommon portion of lymph node swelling and age for KFD.