Pediatric Kikuchi-Fujimoto Disease Diagnosis by Ultrasound-Guided Needle Biopsy

Abstract Background Kikuchi-Fujimoto disease (KFD) is a rare form of non-malignant and self-limited disease. It is quite susceptible to be misdiagnosed because of a lack of diagnostic guidelines. Lymph node biopsy has shown promising results to confirm KFD pathology. Methods This is a retrospective study of patients younger than 18 years old diagnosed with KFD between May 2016 and May 2020 in Shandong Provincial Hospital. Electronic medical records and pathological data were thoroughly reviewed. Ultrasound-guided core needle biopsy (US-CNB) method was performed in all 20 patients. Results A total of 20 pediatric patients were recruited to the study. There were 14 boys and 6 girls (boy:girl = 2.3:1) with a median age of 9.1 ± 3.5 years. Fever and lymphadenopathy were the most frequent complaints. The duration of fever ranged from 6 days to 70 days, with a median of 24.2 days. Leukopenia (45.0%) was more predominant than leukocytosis (10.0%) in this cohort. Laboratory findings showed elevated levels of serum amyloid A (SAA), C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) in 13 (13/20, 65.0%), 5 (5/20, 25.0%) and 17 patients (17/20, 85.0%), respectively. Past episodes of EBV infections in 16 patients (16/18, 88.9%) were confirmed by positive EB-specific viral capsid antigen (EB-VCA) and nuclear antigen (EBNA)-specific IgG antibody tests. Elevated IgE levels were also detected in 9 patients (9/16, 56.3%). The sizes of lymph node swelling ranged from 15–34 mm in long diameter with a median of 23.2 mm. The biopsy sites were mostly selected in the left cervical lymph node (10/20, 50.0%). The histopathological subtype analysis revealed proliferative type (4/20, 20.0%), necrotizing type (13/20, 65.0%), and xanthomatous type (3/20, 15%) of lymphadenopathy. Immunohistochemical staining showed that the infiltrated histiocytes were positive for CD163 (7/20,35.0%), CD68 (15/20, 75.0%), CD123 (6/15, 40.0%) and myeloperoxidase (14/20,70.0%). Corticosteroid therapy remained effective. Patients were followed up for 1 to 4.5 years. All patients had a good prognosis. Recurrence occurred in 3 patients (3/20, 15.0%). Conclusion Diagnosis of KFD depends on pathological and immunohistochemical examinations. US-CNB can serve as a primary pathological diagnostic method for children and young adult patients.