title: Focal eosinophilic necrosis of the liver in patients with underlying gastric or colorectal cancer: CT differentiation from metastasis.
abstract: OBJECTIVE
  To determine the helical CT findings which help differentiate between focal eosinophilic necrosis (FEN) of the liver and metastasis in patients with underlying gastric or colorectal cancer.
  
  
  METHODS
  In 21 patients with underlying gastric and colorectal cancer examined during a recent 18-month period, the presence of FEN (n=90) was proven at CT. The diagnosis was verified by biopsy in eight patients and by the transient nature of the findings related to peripheral eosinophilia (>10%) in the remainder. For comparison, 20 consecutive patients with pathologically proven hepatic metastasis from gastric or colorectal cancer (n=158) were selected. Single-phase helical CT images (7-mm collimation, pitch 1:1) were independently analyzed in a random order by two blinded readers. The parameters evaluated included the margin (depicted border, fuzzy), shape (spherical, non-spherical), attenuation (subtle hypoattenuation, hypoattenuation), and the presence or absence of rim enhancement.
  
  
  RESULTS
  FEN far more frequently showed a fuzzy margin (81%, 84%), subtle hypoattenuation (89%, 91%), and a non-spherical shape (84% for both readers) than metastasis, for which the respective findings were 6%, 22%; 20%, 39%; and 15%, 23%. Rim enhancement was seldom found in FEN (0%, 2%), but was recognized by both readers in 40% of metastases. For all parameters, the results were statistically significant (p < .01), and showed that both readers correctly differentiated FEN from metastasis in 78% of the patients (32/41). Interobserver agreement was, in addition, excellent (kappa = 0.66).
  
  
  CONCLUSIONS
  When focal hepatic lesions with a fuzzy margin, non-spherical shape and subtle hypoattenuation without rim enhancement are found, the possibility of FEN should be considered even in patients with underlying gastrointestinal malignancy.
authors.affiliation: Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Hyun-Jung
authors.initials: HJ
authors.lastname: Jang
authors.forename: Won Jae
authors.initials: WJ
authors.lastname: Lee
authors.forename: Soon Jin
authors.initials: SJ
authors.lastname: Lee
authors.forename: Seung Hoon
authors.initials: SH
authors.lastname: Kim
authors.forename: Hyo K
authors.initials: HK
authors.lastname: Lim
authors.forename: Jae Hoon
authors.initials: JH
authors.lastname: Lim
mesh_terms: D000465:Algorithms; D003110:Colonic Neoplasms / Q000000981:diagnostic imaging*; D004802:Eosinophilia / Q000473:pathology*; D005260:Female; D006801:Humans; D008099:Liver / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging*; D013274:Stomach Neoplasms / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed