title: The clinical and CT imaging features of metanephric adenoma.
abstract: BACKGROUND
  Patients with metanephric adenoma have a good prognosis after undergoing total nephrectomy or local resection with kidney preservation. Accurate diagnosing is important for guiding clinical treatment. Only few previous case reports have been found focusing on the imaging findings of metanephric adenoma.
  
  
  OBJECTIVE
  To evaluate the multislice computed tomography (MSCT) imaging characteristics of metanephric adenoma.
  
  
  METHODS
  The imaging findings in eight patients with metanephric adenoma were studied retrospectively. MSCT was undertaken to investigate tumor location, size, attenuation, cystic or solid appearance, calciﬁcation, capsule sign, and enhancement pattern.
  
  
  RESULTS
  Tumors (mean diameter, 3.3 ± 1.0 cm) were solitary (8/8), solid (7/8) with cystic components (2/8), no calcifications (7/8), had a poorly-deﬁned margin (8/8), were centered in the renal medulla (7/8), compressed the renal pelvis (3/8), and none had retroperitoneal lymph node metastasis. The attenuation of metanephric adenoma tumors was less or equal compared to the renal cortex or medulla on unenhanced CT (30.6 ± 2.6 vs. 36.3 ± 4.6 vs. 33.2 ± 3.9, P > 0.05), while tumor enhancement after administration of an contrast agent was lower than that of normal renal cortex and medulla during all phases (P < 0.05).
  
  
  CONCLUSIONS
  Metanephric adenoma tends to be a solitary, poorly defined margin, isodense or hypodense mass arising from the renal medulla with enhancement less than the cortex and medulla during all phases.
authors.affiliation: Department of Medical Imaging, Subei People's Hospital, Medical School of Yangzhou University, Yangzhou, China.
authors.forename: Qingqiang
authors.initials: Q
authors.lastname: Zhu
authors.forename: Wenrong
authors.initials: W
authors.lastname: Zhu
authors.forename: Jingtao
authors.initials: J
authors.lastname: Wu
authors.forename: Wenxin
authors.initials: W
authors.lastname: Chen
authors.forename: Shouan
authors.initials: S
authors.lastname: Wang
mesh_terms: D000236:Adenoma / Q000150:complications* / Q000175:diagnosis* / Q000628:therapy; D000328:Adult; D003287:Contrast Media; D005260:Female; D006801:Humans; D007472:Iohexol / Q000031:analogs & derivatives; D007680:Kidney Neoplasms / Q000150:complications* / Q000175:diagnosis* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D009392:Nephrectomy; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide
keywords: CT; Metanephric adenoma; computed tomography; pathology