Case Presentation: A 24 year-old woman with history of breast cancer status post mastectomy and adjuvant chemoradiation therapy presented with one week of fevers and cervical lymph node enlargement. On presentation, she was febrile with a temperature of 38.7⁰C. Physical exam was notable for tender, firm, bilateral posterior cervical chain lymphadenopathy up to 1cm. WBC was 1.2 x10E3/uL with an absolute neutrophil count of 400/mm3. She was started on empiric antibiotic therapy for neutropenic fever. Infectious workup including HIV, EBV, CMV, Toxoplasma and Histoplasma testing was negative. Despite antibiotic therapy, her febrile neutropenia persisted. CT of the neck revealed diffuse, homogenous lymphadenopathy up to 1.5cm in her neck and bilateral axillae. Excisional axillary lymph node biopsy was performed that showed necrotizing lymphadenitis with prominent histiocytes. Histologic differential diagnosis included systemic lupus erythematosus (SLE), cat-scratch disease, and Kikuchi lymphadenitis. Lupus serologies were negative and she had no history of cat exposure. Bone marrow biopsy was performed and was unremarkable. Supportive care was provided and by hospital day 12, the patient defervesced and neutropenia resolved. She was discharged with a presumptive diagnosis of Kikuchi disease based on clinical course and lymph node biopsy findings. Follow-up imaging two months later showed resolution of lymphadenopathy and she remained asymptomatic.
Discussion: First described in Japan in 1972, Kikuchi disease, also known as histiocytic necrotizing lymphadenitis or Kikuchi-Fujimoto disease, is a rare but typically benign condition predominantly affecting young women. Patients may present with fever and localized lymphadenopathy, most commonly cervical adenopathy. Nausea, vomiting, myalgias, and night sweats are additional reported symptoms. Other clinical features can include hepatosplenomegaly and leukopenia. Diagnosis is made by excisional lymph node biopsy, though histologic differential diagnosis includes SLE and lymphoma. In fact, some patients have been misdiagnosed as having lymphoma and received chemotherapy. The exact cause of Kikuchi disease is unknown, though it may be an autoimmune-mediated process possibly triggered by a viral pathogen. The condition has been seen in conjunction with SLE and patients should be ruled out for SLE at time of diagnosis and at future visits. There is no definitive treatment though in severe cases, systemic corticosteroids and intravenous immunoglobulin have been used. However, the disease is usually self-limited, resolving in weeks to months. Recurrence is rare.
Conclusions: Kikuchi disease is an uncommon, but benign etiology of lymphadenitis. Strong clinical suspicion and characteristic histopathologic findings are needed for accurate diagnosis. Treatment is supportive and affected patients should receive long-term monitoring for the development of SLE.