title: Epithelioid angiomyolipoma of the kidney: radiological imaging.
abstract: OBJECTIVE
  To review the imaging findings of renal epithelioid angiomyolipomas.
  
  
  METHODS
  Eight patients treated at two institutions were pathologically diagnosed as having epithelioid angiomyolipoma. All of them underwent computed tomography, and four underwent magnetic resonance imaging. The tumor size, existence of fat, heterogeneity, computed tomography attenuation, degree of enhancement, enhancement pattern and magnetic resonance imaging signal intensity were evaluated.
  
  
  RESULTS
  Intratumoral fat was not detected in any of the cases. On unenhanced computed tomography, the intratumoral attenuation was hyperattenuating in six of the seven patients who were examined using this modality. On T2-weighted images, the signal intensity of the solid component, cyst wall or septum was low in three of the four cases. Four of the eight cases were heterogeneous solid-type accompanied by hemorrhage, necrosis or hyalinization. One homogeneous solid-type lesion was large in size and was pathologically accompanied by neither hemorrhage nor necrosis. All three multilocular cystic types were pathologically accompanied by massive hemorrhage in the cystic component. One was accompanied by spontaneous perirenal hematoma.
  
  
  CONCLUSIONS
  The radiological appearance of most epithelioid angiomyolipomas has a tendency to be hyperattenuating on unenhanced computed tomography images, with low intensities on T2-weighted images. They can be heterogeneously solid, homogeneously solid or a multilocular cystic lesion with massive hemorrhage.
authors.affiliation: Department of Diagnostic Radiology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Jitsuro
authors.initials: J
authors.lastname: Tsukada
authors.forename: Masahiro
authors.initials: M
authors.lastname: Jinzaki
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yao
authors.forename: Yoji
authors.initials: Y
authors.lastname: Nagashima
authors.forename: Shuji
authors.initials: S
authors.lastname: Mikami
authors.forename: Hideki
authors.initials: H
authors.lastname: Yashiro
authors.forename: Miwako
authors.initials: M
authors.lastname: Nozaki
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Mizuno
authors.forename: Mototsugu
authors.initials: M
authors.lastname: Oya
authors.forename: Sachio
authors.initials: S
authors.lastname: Kuribayashi
mesh_terms: D000328:Adult; D018207:Angiomyolipoma / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
keywords: angiomyolipoma; computed tomography; magnetic resonance imaging; renal cell carcinoma; renal neoplasms