title: Hepatic epithelioid hemangioendothelioma: findings at CT and MRI including preliminary observations at diffusion-weighted echo-planar imaging.
abstract: OBJECTIVE
  Hepatic epithelioid hemangioendothelioma (EHE) is a rare vascular tumor with low- to intermediate-grade malignant potential. We describe cross-sectional imaging findings of pathologically confirmed EHE including preliminary observations on lesion characteristics and apparent diffusion coefficients (ADCs) at diffusion-weighted MR imaging (DWI).
  
  
  METHODS
  CT and MRI examinations in five patients were retrospectively reviewed. Two radiologists evaluated lesion growth patterns, attenuation, signal intensity characteristics, and contrast enhancement patterns. Additionally, DWI features on low and high b-value images as well as ADCs were assessed in three patients.
  
  
  RESULTS
  Imaging features of EHE included multifocal hepatic disease (n = 5), predominantly subcapsular location (n = 5), coalescence of nodules (n = 5), capsular retraction (n = 3), and intralesional calcifications (n = 3). Contrast-enhanced CT and MR images showed variable degrees of peripheral rim enhancement. T2-weighted MR images, low b-value DWI and ADC maps frequently depicted a "target-sign" appearance of tumor nodules. A markedly hyperintense central area corresponding to hypocellular stroma was surrounded by a moderately hyperintense outer rim reflecting hypercellular tumor regions. The mean ADC of lesions was 1.86 × 10(-3) mm(2)/s.
  
  
  CONCLUSIONS
  Cross-sectional imaging displayed typical features of EHE. The mean ADC value of lesions was found to be relatively high in comparison with other hepatic malignancies, which may be helpful in suggesting the diagnosis.
authors: Department of Radiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany. mbruegel@roe.med.tum.de
authors: Melanie
authors: M
authors: Bruegel
authors: Daniela
authors: D
authors: Muenzel
authors: Simone
authors: S
authors: Waldt
authors: Katja
authors: K
authors: Specht
authors: Ernst J
authors: EJ
authors: Rummeny
mesh_terms: D000328:Adult; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D017352:Echo-Planar Imaging; D005260:Female; D019786:Gadolinium DTPA; D018323:Hemangioendothelioma, Epithelioid / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D006801:Humans; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D036542:Tomography, Spiral Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA