Kikuchi-Fujimoto disease (histiocytic necrotizing lymphadenitis) is a benign, self-limiting form of lymphadenopathy with incompletely understood etiology. More common in young women (20-35 years) and individuals of East Asian descent. Usually presents with painful or tender cervical lymphadenopathy and fever may accompany. Histologically characterized by necrosis foci in paracortex and cortical area, histiocytic infiltration, and absence of neutrophils (without apoptosis) — neutrophil absence is the key distinguishing finding from TB and other necrotizing lymphadenitides. Disease usually spontaneously resolves in 1-6 months and no treatment is needed. Shows clinical and histological similarity to SLE — SLE should be excluded.
Age Range
15-40
Peak Age
25
Gender
Female predominant
Prevalence
Rare
Pathogenesis of Kikuchi disease is not fully understood but viral etiology (EBV, HHV-6, HHV-8, parvovirus B19) or autoimmune mechanism is proposed. CD8+ cytotoxic T-lymphocytes and histiocytes activate and create necrosis foci in paracortex and cortex. Necrosis pattern is 'apoptotic' type — cells die through apoptosis and neutrophils do not migrate to necrosis area (neutrophil absence). This pathological mechanism reflects as necrotic foci on imaging — but necrosis is smaller and more focal than caseous necrosis in TB. Perinodal inflammatory changes may be mild-moderate. Relationship with SLE is based on immunological basis — some patients may develop SLE later or Kikuchi may develop on SLE background. Self-limiting course occurs through immune response balancing — granulomatous healing and fibrosis return node to normal size.
Painful, mildly necrotic lymph node in unilateral cervical posterior triangle in young female (20-35 years), without matting or calcification, with clinical course showing spontaneous regression in 1-6 months is the most characteristic clinical-radiological combination of Kikuchi disease.
Enlarged (usually 1-3 cm), hypoechoic lymph node. Focal necrotic foci (anechoic areas) may be seen — but not as large and prominent as in TB. Hilum may be partially preserved or narrowed. Perinodal changes are mild-moderate. Usually unilateral, 1-3 nodes involved (cervical posterior triangle).
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Enlarged, hypoechoic lymph node with focal necrotic foci in cervical posterior triangle with mild perinodal changes — Kikuchi disease should be considered in young female.
Hilar or mixed vascularity pattern on Doppler — prominent peripheral vascularity as in malignant pattern is not expected. Vascularity may be increased (active inflammation). Avascular zones in necrotic foci. RI usually within normal limits.
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Hilar/mixed vascularity pattern in lymph node with no peripheral vascularity detected — consistent with benign/inflammatory character.
Homogeneously or mildly heterogeneously enhancing lymph nodes on contrast-enhanced CT. Necrotic foci may be seen as small low-density areas. Perinodal fat stranding is mild-moderate. Matting not expected (different from TB). No calcification. Usually unilateral cervical (level V).
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Homogeneously/mildly heterogeneously enhancing lymph nodes in cervical posterior triangle with mild perinodal changes — no matting or calcification detected.
Mild-moderate diffusion restriction on DWI — ADC usually 0.9-1.3 × 10⁻³ mm²/s. Heterogeneous ADC in necrotic foci. Intermediate-high signal on T2. Homogeneous or mildly heterogeneous enhancement post-contrast.
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Mild-moderate diffusion restriction in lymph node on DWI (ADC: ... × 10⁻³ mm²/s), malignancy is of low probability.
Mild-moderate FDG uptake on PET-CT (SUVmax usually 2-6). Localized uptake — usually unilateral cervical. Widespread uptake not expected. Lower uptake degree than lymphoma.
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Lymph nodes with localized mild-moderate FDG uptake (SUVmax: ...) in cervical region — inflammatory lymphadenopathy is probable.
Soft tissue density lymph nodes on non-contrast CT. No calcification. Homogeneous internal structure — no large necrosis areas seen. Perinodal fat planes partially preserved.
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Soft tissue density cervical lymph nodes without calcification.
Criteria
Histiocytic proliferation predominant, minimal necrosis. Early stage.
Distinct Features
Homogeneously enlarged node on imaging, necrotic foci minimal. May mimic lymphoma.
Criteria
Prominent necrosis foci, apoptotic debris, histiocytic infiltration. Most common type.
Distinct Features
Mildly heterogeneous/necrotic node on imaging. May mimic TB but no matting.
Criteria
Foamy histiocytes (foamy macrophages) predominant. Represents healing phase.
Distinct Features
Shrinking node on imaging, necrosis resolving. In spontaneous healing process.
Distinguishing Feature
TB shows rim enhancement, matting, calcification, and multi-region involvement — Kikuchi shows mildly heterogeneous enhancement, no matting, no calcification, and unilateral cervical predilection.
Distinguishing Feature
NHL shows intense FDG uptake, widespread involvement, conglomerate LAP — Kikuchi shows low-moderate FDG, localized involvement, self-limiting course, and young female predilection.
Distinguishing Feature
Reactive LAP has no necrosis and oval shape is preserved — Kikuchi shows focal necrosis foci but no matting.
Distinguishing Feature
CSD shows cat contact history, prominent perinodal changes, inoculation point — Kikuchi has no cat contact, mild perinodal changes, and young female predilection.
Urgency
routineManagement
conservativeBiopsy
NeededFollow-up
3-monthKikuchi diagnosis is usually made by excisional biopsy — FNA may be insufficient (architectural assessment required). Main reason for biopsy is to exclude lymphoma and TB. Disease is self-limiting and no specific treatment needed — symptomatic treatment (NSAID, antipyretics) is sufficient. Rare recurrence (3-4%) has been reported. Due to SLE association, ANA and anti-dsDNA should be checked, clinical follow-up for long-term SLE development is recommended. Follow-up US at 3 months to assess regression.
Kikuchi disease is a benign and self-limiting condition. Treatment is usually symptomatic (NSAIDs). Unnecessary biopsy is often performed due to lymphoma suspicion — Kikuchi should be considered in young Asian women with fever + leukopenia + posterior cervical LAP. Follow-up and ANA monitoring is recommended due to SLE transformation risk (3-10%). Rare recurrence (3-4%) has been reported.