title: Imaging characteristics of sinonasal organized hematoma.
abstract: BACKGROUND
  Sinonasal organized hematoma is a rare benign disease that may be mistaken for malignancy.
  
  
  OBJECTIVE
  To define the imaging characteristics of sinonasal organized hematoma.
  
  
  METHODS
  We retrospectively reviewed computed tomography (CT) images of eight patients (4 male patients, 4 female patients; mean age, 40 years; range, 9-83 years) with pathologically proven sinonasal organized hematomas; magnetic resonance imaging (MRI) was performed in one patient among them. The following lesions characteristics were analyzed: size, shape, location, expansile nature, density, signal intensity, internal structure, enhancement pattern, and surrounding bony wall change.
  
  
  RESULTS
  The lesion sizes were in the range of 2-5.2 cm (mean, 3.55 cm), and the shapes were lobular, lumpy, or nodular. They were located in the nasal cavity (n = 1), maxillary sinuses (n = 2), or both nasal cavities and maxillary sinuses (n = 5). Expansile lesions with locally aggressive margins were observed in two cases. All lesions were hyperdense on precontrast CT scans; the smaller lesions showed even hyperdensity, whereas the larger lesions showed uneven density. The signal intensity was mixed on MRI, consisting of hemorrhage, fibrosis, and neovascularization. Papillary or frond-like enhancement was noted after contrast injection. All cases showed smooth erosion of the medial walls of the maxillary sinuses, and the epicenters were the secondary maxillary ostia. Two lesions showed erosion of the lateral walls of the maxillary sinuses and were expansile in nature. Non-hemorrhagic polyps accompanied the organized hematomas in three cases.
  
  
  CONCLUSIONS
  Although sinonasal organized hematoma can be mistaken for a malignant tumor, the following characteristic imaging findings facilitate the diagnosis of an organized hematoma: erosion of the bony sinus walls, markedly heterogeneous signal intensity, and papillary or frond-like enhancement.
authors.affiliation: Department of Radiology, Chung-Ang University College of Medicine, Seoul, Republic of Korea.
authors.forename: Joonho
authors.initials: J
authors.lastname: Hur
authors.affiliation: Department of Radiology, Chung-Ang University College of Medicine, Seoul, Republic of Korea Department of Radiology, Kangwon National University College of Medicine, Chuncheon, Republic of Korea mirachx@naver.com.
authors.forename: Jae Kyun
authors.initials: JK
authors.lastname: Kim
authors.affiliation: Department of Radiology, Chung-Ang University College of Medicine, Seoul, Republic of Korea.
authors.forename: Jun Soo
authors.initials: JS
authors.lastname: Byun
authors.affiliation: Department of Radiology, Chung-Ang University College of Medicine, Seoul, Republic of Korea.
authors.forename: Woong Jae
authors.initials: WJ
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D005260:Female; D006406:Hematoma / Q000175:diagnosis*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009296:Nasal Cavity / Q000000981:diagnostic imaging* / Q000473:pathology*; D010254:Paranasal Sinus Diseases / Q000175:diagnosis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult
keywords: Hematoma; computed tomography; magnetic resonance imaging; nasal cavity; paranasal sinuses