title: Hematoma-like mass of the maxillary sinus.
abstract: CONCLUSIONS
  We have reported a non-neoplastic, heterogeneous, hemorrhagic lesion of the maxillary sinus characterized by a mixture of dilated vessels, hemorrhage and fibrin exudation. This lesion should be distinguished from hemangioma and hematoma. We propose the name "hematoma-like mass of the maxillary sinus" for this disease, based on its histological characteristics.
  
  
  OBJECTIVE
  To describe the clinicopathological characteristics of a non-neoplastic, heterogeneous, hemorrhagic lesion of the maxillary sinus associated with mucosal swelling and bone destruction.
  
  
  METHODS
  This was a retrospective review of six patients who were treated surgically for masses and met the following criteria: (i) CT demonstrated an expanding unilateral maxillary lesion, with thinning or destruction of the surrounding bony tissue; (ii) MRI demonstrated a heterogeneous mass; (iii) macroscopically, a mass with a hemorrhagic and heterogeneous appearance was observed; and (iv) histologically, a non-neoplastic tissue with mucosal hemorrhage was observed.
  
  
  RESULTS
  The clinical features of this disease, such as a mass expanding from the maxillary sinus with bone destruction, resembled those of maxillary carcinoma. However, CT and MRI provided sufficient information to differentiate this condition from malignancy. Resection was straightforward due to a firm capsule. Characteristic histological findings were a mixture of dilated vessels, hemorrhage and fibrin exudation.
authors.affiliation: Department of Biology and Function in the Head and Neck, Graduate School of Medicine, Yokohama City University, Japan.
authors.forename: Mizuho
authors.initials: M
authors.lastname: Yagisawa
authors.forename: Junichi
authors.initials: J
authors.lastname: Ishitoya
authors.forename: Mamoru
authors.initials: M
authors.lastname: Tsukuda
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001707:Biopsy, Needle; D003937:Diagnosis, Differential; D005260:Female; D006391:Hemangioma / Q000175:diagnosis* / Q000601:surgery; D006406:Hematoma / Q000175:diagnosis* / Q000601:surgery; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008443:Maxillary Sinus / Q000473:pathology*; D008444:Maxillary Sinus Neoplasms / Q000175:diagnosis* / Q000601:surgery; D008875:Middle Aged; D015508:Nasal Obstruction / Q000175:diagnosis / Q000209:etiology; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed