What is the role of imaging studies in the workup of Kikuchi disease?

Updated: Nov 13, 2020
  • Author: John Boone, MD; Chief Editor: Sara J Grethlein, MD, FACP  more...
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Answer

Diagnostic imaging studies confirm the presence of enlarged lymph nodes in the affected areas, but they cannot specifically confirm a diagnosis of Kikuchi disease.

On computed tomography (CT) scanning and magnetic resonance imaging (MRI), uniform enlargement of lymph nodes in affected areas is noted. Postcontrast enhancement may be observed.

In a study of 96 patients with Kikuchi disease, Kwon et al reported the following CT findings [33] :

  • Homogeneous lymph node enlargement (83.3% of patients)
  • Perinodal infiltration (81.3%)
  • Prominent areas of low attenuation suggestive of focal necrosis (16.7%)

Shim et al reported that CT imaging pattern analysis of cervical lymph nodes can be used to help differentiate Kikuchi disease from tuberculous lymphadenopathy and reactive hyperplasia. In their study, high cortical attenuation combined with an indistinct nodal architecture supported the diagnosis of Kikuchi disease. In cases of non-necrotic lymphadenopathy, the ratio of nodal cortical attenuation to the adjacent muscle (NCA/M) was significantly higher in Kikuchi disease: 1.67 ± 0.20, compared with1.49 ± 0.20 in reactive hyperplasia and 1.47 ± 0.21 in tuberculous lymphadenopathy. [24]

In a study by Kato et al of MRI findings in nine patients with Kikuchi disease, cervical lymphadenopathy showed predominantly a unilateral distribution at levels II-V. On T2-weighted images, areas of hypointensity were visible at the peripheries of enlarged cervical nodes; these corresponded to histopathological findings of coagulative necrosis. [34]

On ultrasonography, Ryoo et al reported that the following lymph node characteristics are typical of Kikuchi disease [35] :

  • Echogenic hilum
  • Posterior neck involvement
  • Absence of internal calcification
  • Absence of necrosis (rarely, presence of partial necrosis)
  • Normal vascular pattern on power Doppler ultrasound (ie, hilar vascular structures are central or branch radially from the hilum in both longitudinal and transverse planes)

Chest radiography findings are generally unremarkable in Kikuchi disease. However, a chest radiograph is recommended in the evaluation of cervical adenopathy to look for evidence of tuberculosis or malignancy. [8]


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