title: Sinonasal organized hematoma: CT and MR imaging findings.
abstract: OBJECTIVE
  Sinonasal organized hematoma (OH) is an uncommon, nonneoplastic benign condition that can be locally aggressive. The purpose of this work was to characterize the CT and MR imaging findings of sinonasal OH.
  
  
  METHODS
  CT (n = 11) and MR (n = 10) images of 12 patients (9 men and 3 women; mean age, 41 years; range, 12-76 years) with pathologically proved sinonasal OH were retrospectively reviewed. Particular attention was put on the location, shape, size, extent, internal architecture, and enhancement pattern of the lesion and associated sinus wall change.
  
  
  RESULTS
  The lesions were seen as an expansile (n = 9) or nonexpansile (n = 3) mass, ranging in size from 2.2 to 6.0 cm (mean, 4.2 cm), primarily involving the maxillary sinus (n = 11) or nasal cavity (n = 1) unilaterally. The ipsilateral nasal cavity was also involved in 9 of 11 maxillary sinus lesions. Smooth sinus wall erosion other than the medial maxillary sinus wall was noted in 8 lesions. The internal architecture was best displayed on T2-weighted MR images on which all of the lesions were seen as a mixture of marked heterogeneous hypointensity and isointensity, surrounded by a hypointense peripheral rim, reflecting histologic heterogeneity of the lesion composed of hemorrhage, fibrosis, and neovascularization. Marked irregular nodular, papillary, or frondlike enhancement at the areas of neovascularization was also a typical finding seen in all of the lesions.
  
  
  CONCLUSIONS
  An expansile soft tissue mass, smooth sinus wall erosion, marked heterogeneous signal intensity with a hypointense peripheral rim on T2-weighted MR images, and marked irregular nodular, papillary, or frondlike enhancement are characteristic CT and MR imaging findings of sinonasal OH.
authors.affiliation: Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: E Y
authors.initials: EY
authors.lastname: Kim
authors.forename: H-J
authors.initials: HJ
authors.lastname: Kim
authors.forename: S-K
authors.initials: SK
authors.lastname: Chung
authors.forename: H-J
authors.initials: HJ
authors.lastname: Dhong
authors.forename: H Y
authors.initials: HY
authors.lastname: Kim
authors.forename: Y J
authors.initials: YJ
authors.lastname: Yim
authors.forename: S T
authors.initials: ST
authors.lastname: Kim
authors.forename: P
authors.initials: P
authors.lastname: Jeon
authors.forename: Y-H
authors.initials: YH
authors.lastname: Ko
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D005260:Female; D006406:Hematoma / Q000175:diagnosis*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009668:Nose Diseases / Q000175:diagnosis*; D010254:Paranasal Sinus Diseases / Q000175:diagnosis*; D014057:Tomography, X-Ray Computed / Q000379:methods*