title: Gray scale and power Doppler study of biopsy-proven Kikuchi disease.
abstract: OBJECTIVE
  Kikuchi disease is a benign, self-limiting cause of cervical lymphadenopathy. It can show sonographic features similar to those of other common causes of lymphadenopathy. The purpose of this study was to characterize the sonographic features of Kikuchi disease that can contribute in differentiating between Kikuchi disease and other diseases causing cervical lymphadenopathy.
  
  
  METHODS
  Sonographic findings of 175 patients with biopsy-proven Kikuchi disease were retrospectively reviewed. The mean age of the patients was 27.3 years, and the female to male ratio was 3.5:1. All patients had undergone sonographically guided core biopsy. Pathologic findings were classified into proliferative (n = 57), necrotizing (n = 109), and xanthomatous (n = 9) types. On gray scale sonography, lymph nodes were assessed by their size, shape (shortest/longest axis ratio), location, echogenicity, presence of conglomeration, gross necrosis, calcification, echogenic nodal hilum, and increased perinodal echogenicity. The vascular pattern was assessed on power Doppler imaging.
  
  
  RESULTS
  The mean maximum diameter of the lymph nodes was 1.6 cm. Forty-four percent of them (77 of 175) were oval (shortest/longest axis ratio, 0.5-0.7) and 48% (84 of 175) were elongated (shortest/longest axis ratio, <0.5). Most were located in levels II and V. Seventeen lymph nodes showed gross necrosis, and none showed calcification. One hundred fifty-two lymph nodes (86.8%) had an echogenic hilum, and 76% (133 of 175) showed increased perinodal echogenicity. Increased perinodal echogenicity was seen in 93.5% of the necrotizing type (102 of 109) and 43.8% of the proliferative type (25 of 57); the difference between the two types was statistically significant (P = .001). Normal (n = 161), displaced (n = 13), and absent (n = 1) hilar vascularity was seen on power Doppler studies.
  
  
  CONCLUSIONS
  Sonographic findings of Kikuchi disease can contribute to the differentiation between Kikuchi disease and other causes of cervical lymphadenopathy.
authors.affiliation: Department of Radiology, Korea University Guro Hospital, Korea University College of Medicine, 97 Guro-dong, Guro-gu, Seoul 152-703, Korea.
authors.forename: Jung Lim
authors.initials: JL
authors.lastname: Yoo
authors.forename: Sang-Il
authors.initials: SI
authors.lastname: Suh
authors.forename: Young Hen
authors.initials: YH
authors.lastname: Lee
authors.forename: Hyung Suk
authors.initials: HS
authors.lastname: Seo
authors.forename: Kyoung Min
authors.initials: KM
authors.lastname: Kim
authors.forename: Bong Kyung
authors.initials: BK
authors.lastname: Shin
authors.forename: Joon Young
authors.initials: JY
authors.lastname: Song
authors.forename: Hae Young
authors.initials: HY
authors.lastname: Seol
mesh_terms: D000293:Adolescent; D000328:Adult; D001706:Biopsy; D016009:Chi-Square Distribution; D002648:Child; D005260:Female; D020042:Histiocytic Necrotizing Lymphadenitis / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D018084:Ultrasonography, Interventional