Kikuchi-Fujimoto Disease Associated with Hashimoto's Thyroiditis: A Case Report.

BACKGROUND: Kikuchi-Fujimoto disease (KFD) is a rare, benign, and self-limiting disorder characterized primarily by cervical lymphadenopathy and fever. Although the disease has been reported worldwide, it is more frequently observed in young women of Asian descent. The etiology of this disease remains unclear. Kikuchi-Fujimoto disease has been reported in association with several autoimmune disorders. Its coexistence with Hashimoto's thyroiditis is rarely described in the literature. OBJECTIVE: To present a case of KFD associated with Hashimoto's thyroiditis and highlight the importance of considering this diagnosis in patients with autoimmune disorders. CASE PRESENTATION: A 37-year-old woman with a known history of Hashimoto's thyroiditis who presented with rapidly enlarging cervical lymphadenopathy. Laboratory investigations, Ultrasonography, and Excisional lymph node biopsy were performed. RESULTS: Laboratory tests revealed mild anemia, elevated ESR, and positive anti-TPO antibodies. Ultrasound showed multiple hypoechoic cervical lymph nodes. Biopsy confirmed KFD with characteristic histopathological features. The patient improved spontaneously without specific treatment. CONCLUSIONS AND SIGNIFICANCE: This case underscores the importance of including KFD in the differential diagnosis of cervical lymphadenopathy, particularly in young women with autoimmune diseases. Clinicians should be aware of this rare association to avoid misdiagnosis and unnecessary interventions.