MISDIAGNOSIS OF KIKUCHI-FUJIMOTO DISEASE: THE IMPORTANCE OF TIMELY HISTOPATHOLOGY IN LYMPHADENITIS

ABSTRACT

Background: Febrile lymphadenopathy not responding to first line antibiotics in a patient hailing from or with a history of travel to tuberculosis endemic countries is often primarily diagnosed as extra-pulmonary tuberculosis. However, histiocytic necrotizing lymphadenitis or Kikuchi-Fujimoto Disease(KFD) presents with similar clinical features. Etiological theories of KFD include viral agents, autoimmunity, and physicochemical factors such as leaking implants. Although KFD has classically been described in young Asian females, recent studies show men and women can be equally affected, with cases increasingly being reported from the USA and Europe as well. Availability bias amongst physicians can lead to misdiagnoses, especially in patients from tuberculosis endemic countries. Objectives: To describe a case of misdiagnosis of KFD in an adolescent. Design/Method: Case report. Results: A 16-year-old male from a tuberculosis endemic country, with a history of asthma, eczema and excision of omental infarct, presented with sub-occipital lymphadenopathy which resolved with antibiotics. Six months later, he complained of tender left cervical lymphadenopathy, associated with fever and fatigue, which lasted for a month. Two courses of antibiotics failed to decrease symptoms. Based on his clinical history, he was started on empirical anti-tubercular medications despite negative tests for tuberculosis. However, his symptoms began to worsen after three weeks of this treatment, and he developed high evening rise of temperature associated with chills, night sweats, frontal headache, pedal edema and generalized pruritic maculopapular rash. Laboratory workups revealed leukopenia (WBC3830/μL);elevated Erythrocyte sedimentation rate (29 mm/h), C-reactive protein (68.6 mg/dL), Aspartate Aminotransferase(95 U/L) and Alanine Aminotransferase(61 U/L). Rapid antigen test for SARS-CoV2 was negative, and no appreciable levels of SARS-CoV-2 IgG antibodies were detected. Investigations for Tuberculosis, EBV, CMV, Dengue, Malaria, Typhoid, Leptospirosis and Scrub typhus were all negative. Chest X-ray and abdomen ultrasound scan were normal. Histopathological analysis of the excised cervical lymph nodes demonstrated crescentic histiocytes and karyorrhexis in a background of coagulative necrosis. Neutrophils, granulomas and acid-fast bacilli were absent. Immunohistochemistry was positive for CD3, CD20, CD68;and negative for CD15, CD30 and PAX-5. A diagnosis of KFD was made, and patient was given supportive treatment only. His symptoms rapidly resolved within 48 hours, with complete resolution by three months. Conclusion: It is important to raise awareness of KFD, a benign and self-limiting condition with good prognosis, which has many clinical symptoms mimicking grave conditions like extra-pulmonary tuberculosis, SLE and lymphomas. Timely histopathological analysis can help avoid anxiety surrounding a misdiagnosis and adverse reactions due to unnecessary toxic treatments.