title: Adrenal adenomas: relationship between histologic lipid-rich cells and CT attenuation number.
abstract: OBJECTIVE
  To evaluate the relationship between lipid-rich cells of the adrenal adenoma and precontrast computed tomographic (CT) attenuation numbers in three clinical groups.
  
  
  METHODS
  Thirty-five surgically resected adrenal adenomas were used. The clinical diagnoses of the patients included 13 cases of primary aldosteronism, 15 cases of Cushing's syndrome, and 7 non-functioning tumors. The number of lipid-rich clear cells was counted using a microscopic eyepiece grid that contained 100 squares. The results were expressed as the percentages of lipid-rich areas.
  
  
  RESULTS
  There was a strong inverse linear relationship between the percentage of lipid-rich cells and the precontrast CT attenuation number (R(2)=0.724, P<0.0001). There were significantly more lipid-rich cells in the primary aldosteronism and non-functioning tumor cases compared to cases of Cushing's syndrome (P=0.007 and 0.015, respectively). The CT attenuation numbers of the primary aldosteronism cases were significantly lower than those of Cushing's syndrome (P=0.0052). Furthermore, the CT attenuation numbers of the non-functioning tumor cases were lower than those of Cushing's syndrome cases.
  
  
  CONCLUSIONS
  We showed that adrenal adenomas in primary aldosteronism and non-functioning tumors contain significantly more lipid-rich cells than those in Cushing's syndrome. They also showed significantly lower attenuation than that in Cushing's syndrome on CT scans. Our results suggest that precontrast CT attenuation numbers may be helpful in the differentiation of adenomas from non-adenomatous lesions, which include malignancies.
authors.affiliation: Department of Diagnostic Radiology, Tohoku University, School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8574, Japan. yamataka@rad.med.tohoku.ac.jp
authors.forename: Takayuki
authors.initials: T
authors.lastname: Yamada
authors.forename: Tadashi
authors.initials: T
authors.lastname: Ishibashi
authors.forename: Haruo
authors.initials: H
authors.lastname: Saito
authors.forename: Toshio
authors.initials: T
authors.lastname: Matsuhashi
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Majima
authors.forename: Masashi
authors.initials: M
authors.lastname: Tsuda
authors.forename: Shoki
authors.initials: S
authors.lastname: Takahashi
authors.forename: Takuya
authors.initials: T
authors.lastname: Moriya
mesh_terms: D000236:Adenoma / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology*; D000273:Adipose Tissue / Q000473:pathology*; D000310:Adrenal Gland Neoplasms / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology*; D000328:Adult; D000368:Aged; D003480:Cushing Syndrome / Q000150:complications / Q000473:pathology; D005260:Female; D006801:Humans; D006929:Hyperaldosteronism / Q000150:complications / Q000473:pathology; D008297:Male; D008875:Middle Aged; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed