A 29 years female patient pressented to her family physician with a big unilateral cervical lymphadenopathy of two weeks of evolution. She refers fever at the begining of the episode after catching a cold with a maximum body temperature of 38º with sore throat, in treatment with antipyretics with resolution of the fever but pain in lymph node. On the first examination, the patient had no fever, and had multiple and painful lymphadenopathies in the right side of the neck. No adhesion to the surrounding tissue. No hepatomegaly or splenomegal. No weight loss, no travels, no family illness.The ultrasound in primary care evidence: multiple enlarged lymph nodes in the right cervical upper jugular measuring the largest 45x15mm. Blood examination laboratory tests showed a white blood cell count of 2,5×109 L, C reactive protein 9,43 mg/dl Lymph noce escisional biobsy showed numerous lymphohistiocytic cells, multiple necrotic areas with marked karyorrhexis and prolifetation of histiocytes, The diagnosis was: Kikuchi-Fujimoto diseaseKikuchi-Fujimoto disease is a rare, bening, self-limited disorder characterized by subacute or acute cervical lymphadenopathy, often accompained by fever, predominantly in young adults of Asian descent bit reported worldwide The etiology ramains unclear, bt current evidence implicates an aberrant immune response, possibly triggered by viral infection or autoimmune mechanisms, with a predominance of CD 8 T cells and plasmacytoid dentritic cells in affected lymph nodes. Diagnosis is established by escisional lymph node biopsy, which reveals characteristic paracortical necrosis with abundant karyrrhectic debris, proliferation of histiocytes, and absence of neutrophils and eosinophils.The clinical and histopathologyfical features can mimic lymphoma and systemic lupus erythematosus, making accurate disgnosis essential to avoid unnecessary or inappropriate therapy.Treatment is primarily supportive, as the disease typically resolves spontaneously within 1-4 months. Nonsteroidal anti-inflammatory drugs and analgesics are first-line for symptom control. Corticosteroids may be considered in severe or persistent cases.   Long-term follow up is recommended due to small but subnotable risk of subsequent development of lupus erythematosus.Accurate clinicopathologic recognition is  crucial, particulary because it can be mistaken for malignant lymphoma