title: Multiphasic helical CT criteria for differentiation of recurrent neoplasm and desmoplastic reaction after laparoscopic resection of renal mass lesions.
abstract: OBJECTIVE
  Differentiation of recurrent neoplasm and desmoplastic reaction following laparoscopic resection of renal mass lesions poses a problem. The usefulness of multiphasic helical CT-generated criteria based on enhancement and morphologic characteristics was investigated.
  
  
  METHODS
  The findings in 5 female and 12 male patients aged 29 to 68 years having renal-cell carcinoma (11-38 mm; N = 15) or solitary angiomyolipomas (N = 2) treated by laparoscopic resection (N = 15) or open segmental surgery (N = 2) were analyzed. Multiphasic helical CT was performed in the preenhancement, arterial corticomedullary, parenchymal, and excretory phases generating 2.5- to 7-mm slices.
  
  
  RESULTS
  Both recurrent neoplasms showed median postcontrast enhancement of 119 HU in the arterial corticomedullary phase; the median enhancement of desmoplastic masses was 48 HU. In the parenchymal and excretory phase, recurrent neoplasms showed progressive loss of enhancement, whereas desmoplastic lesions sustained enhancement at about the same level. Recurrent neoplasms presented a defined mass with characteristic spiculation, whereas desmoplastic reaction was characterized by an ill-defined mass with spidery projections extending to abutting fat and residual fascial planes. On 2- to 3-month follow-up scans, recurrent neoplasms showed progressive increases in size and desmoplastic reaction a sharp decrease.
  
  
  CONCLUSIONS
  Enhancement of the mass at the operative site on arterial corticomedullary-phase CT to >90 HU strongly suggests recurrent renal-cell carcinoma, while progressive decrease in size on 1- to 3-month follow-up CT suggests a desmoplastic reaction.
authors.affiliation: Department of Radiology, Tulane University Health Sciences Center, New Orleans, Louisiana, USA. elang1@tulane.edu
authors.forename: E K
authors.initials: EK
authors.lastname: Lang
authors.forename: R
authors.initials: R
authors.lastname: Thomas
authors.forename: R
authors.initials: R
authors.lastname: Davis
authors.forename: B
authors.initials: B
authors.lastname: Shore
authors.forename: G
authors.initials: G
authors.lastname: Ruiz-Deya
authors.forename: R J
authors.initials: RJ
authors.lastname: Macchia
authors.forename: B
authors.initials: B
authors.lastname: Gayle
authors.forename: R A
authors.initials: RA
authors.lastname: Watson
authors.forename: F
authors.initials: F
authors.lastname: Richter
mesh_terms: D000328:Adult; D000368:Aged; D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging* / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D005355:Fibrosis / Q000000981:diagnostic imaging* / Q000209:etiology / Q000473:pathology; D006801:Humans; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D010535:Laparoscopy / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000209:etiology / Q000473:pathology; D009392:Nephrectomy / Q000009:adverse effects*; D012189:Retrospective Studies; D036542:Tomography, Spiral Computed