Kikuchi-Fujimoto Disease in a Patient With Systemic Lupus Erythematosus: A Case Report.

Kikuchi-Fujimoto disease (KFD), or histiocytic necrotizing lymphadenitis, is a rare, self-limiting syndrome characterized by fever and lymphadenopathy, most commonly cervical, though other nodal regions may be involved. It is well recognized to occur in patients with systemic lupus erythematosus (SLE), with which it shares substantial clinical and histopathologic overlap, often mimicking a lupus flare or a lymphoproliferative disorder. We report the case of a 43-year-old woman with a known history of SLE, maintained on hydroxychloroquine and low-dose prednisolone, who presented with a two-week history of fever, chills, rigors, and generalized body aches. She was found to have elevated inflammatory markers, hypocomplementemia, a markedly elevated antinuclear antibody titer, and elevated anticardiolipin IgM, with imaging demonstrating marked right axillary and bilateral pelvic/iliac lymphadenopathy. Excisional lymph node biopsy demonstrated extensive necrotizing lymphadenitis with karyorrhectic debris and a predominantly T-cell infiltrate, without granulomas, and with negative infectious and Epstein-Barr virus studies, consistent with KFD. Bone marrow examination excluded an underlying hematologic malignancy, and a low HScore made hemophagocytic lymphohistiocytosis unlikely. The patient was treated with escalation of corticosteroid therapy and continuation of hydroxychloroquine, achieving clinical recovery with resolution of fever. This case highlights the importance of recognizing KFD as a cause of fever and lymphadenopathy in patients with SLE, and underscores the value of histopathologic confirmation in guiding appropriate management.