Broadening the Clinical Spectrum of Kikuchi–Fujimoto Disease: Mini Case Series

Introduction Kikuchi–Fujimoto disease, also called histiocytic necrotizing lymphadenitis, is a rare, usually self-limiting inflammatory condition of unknown aetiology. It classically presents with acute-to-subacute, painful, localized, or limited regional lymphadenopathy, often associated with fever. We present three cases demonstrating the clinical heterogeneity of Kikuchi–Fujimoto disease. Case 1 A 24-year-old male of Fijian-Indian background presented with three weeks of daily fevers, drenching night sweats, 5 kg weight loss, peripheral joint oligoarthritis, and oral mucosal erosions. Examination revealed mildly tender generalised lymphadenopathy without hepatosplenomegaly. FDG-PET demonstrated generalized, intensely FDG-avid lymphadenopathy, and widespread peripheral small and large joint synovitis. Core biopsy of a left axillary lymph node showed histiocytic necrotising lymphadenitis. Case 2 A 23-year-old male of Fijian-Indian background presented with six weeks of daily fevers, drenching night sweats, 11 kg weight loss, peripheral joint polyarthritis, rhinitis, abdominal pain, and non-bloody diarrhoea. Examination revealed mildly tender generalised lymphadenopathy without hepatosplenomegaly. Fecal calprotectin was non-elevated, and he had significant hyperferritinaemia. Bone marrow evaluation demonstrated normocellular marrow with increased haemophagocytic activity. FDG-PET demonstrated generalised, intensely FDG-avid lymphadenopathy (Figure 1). Core biopsy of a right axillary lymph node showed histiocytic necrotizing lymphadenitis. Figure 1. Whole-body FDG-PET scan of case 2; representative coronal slices demonstrating intensely FDG-avid cervical, supraclavicular, axillary, intra-abdominal, inguinal, and femoral lymphadenopathy. Case 3 A 22-year-old female of Chinese background presented with three weeks of daily fevers, painful cervical lymphadenopathy, generalized myalgias, and oral mucositis. Right axillary lymphadenopathy had been present for over three months. Fine-needle aspiration biopsy of a right axillary lymph node showed histiocytic necrotizing lymphadenitis. Symptoms improved with moderate-dose prednisolone tapered over four months; however, fluctuating axillary lymphadenopathy persisted for approximately four years. Repeat axillary lymph node biopsy at two years did not demonstrate evidence of malignancy. Conclusion The clinical presentation of Kikuchi–Fujimoto disease may be dominated by constitutional, musculoskeletal, mucosal, or gastrointestinal features rather than lymphadenopathy. Appreciating the diverse clinical features may reduce diagnostic delay and misdiagnosis.