title: Adrenal hematoma after nephrectomy.
abstract: OBJECTIVE
  The objective of our study was to retrospectively define the incidence of adrenal hematoma on CT or MRI after nephrectomy.
  
  
  METHODS
  Between January 2008 and June 2009, 465 patients underwent nephrectomy at our institution. Of these, patients without both preoperative and postoperative abdominal CT or MR studies within 6 months of surgery (n = 83) and those with documented adrenalectomy at the time of radical nephrectomy (n = 33) were excluded. Thus, 349 patients (292 male, 57 female; mean age, 60.2 years; range, 2-88 years) were included in the study. Preoperative and postoperative CT or MR studies were reviewed by two radiologists in consensus for the presence or absence of adrenal hematoma. Diagnosis of adrenal hematoma was made by imaging findings and follow-up. The incidence of adrenal hematoma was calculated with a 95% CI.
  
  
  RESULTS
  Of the 349 patients (partial nephrectomy, n = 232; radical nephrectomy, n = 117), 19 patients developed adrenal hematoma after nephrectomy (partial nephrectomy, n = 12; radical nephrectomy, n = 7) with an incidence of 5.4% (95% CI, 3.1-7.8%). All adrenal hematomas were located on the side of nephrectomy (right adrenal gland, n = 8; left adrenal gland, n = 11). In nine patients, the adrenal hematoma appeared as a round or oval lesion on postoperative imaging with a mean size of 2.6 cm (range, 1.5-4.0 cm). In 10 patients, the adrenal hematoma appeared as diffuse enlargement of the adrenal gland on postoperative imaging with a mean thickness of 1.3 cm (range, 0.6-1.8 cm).
  
  
  CONCLUSIONS
  An adrenal hematoma was identified in 5.4% of patients on CT or MRI after nephrectomy. A new round or oval adrenal mass after nephrectomy should be differentiated from a metastasis.
authors.affiliation: Department of Radiology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA.
authors.forename: Kewalee
authors.initials: K
authors.lastname: Sasiwimonphan
authors.forename: Naoki
authors.initials: N
authors.lastname: Takahashi
authors.forename: Bradley C
authors.initials: BC
authors.lastname: Leibovich
authors.forename: Akira
authors.initials: A
authors.lastname: Kawashima
mesh_terms: D000293:Adolescent; D000307:Adrenal Gland Diseases / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000453:epidemiology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D005260:Female; D006406:Hematoma / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009392:Nephrectomy / Q000009:adverse effects*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed