title: Incidental angiomyolipoma resected during renal surgery for an enhancing renal mass.
abstract: OBJECTIVE
  To review the outcomes of surgery for renal angiomyolipoma (AML, a benign renal neoplasm that often appears as an enhancing renal mass on imaging) removed at a centre that manages AML conservatively, as typically the presence of tumour fat content detected on imaging leads to its diagnosis, but occasionally these tumours resemble conventional RCC, leading to their surgical extirpation.
  
  
  METHODS
  We retrospectively report data on 44 consecutive patients who had renal surgery with a pathological diagnosis of AML at our institution from 1988 to 2008. Patient demographics, intraoperative variables and postoperative outcomes are reported.
  
  
  RESULTS
  Of the 44 patients (40 women, 91%, and four men, 9%), most were asymptomatic (36, 82%), were unsuspected on imaging (40, 91%), had a solitary lesion (38, 86%), and all had a normal contralateral kidney. Patients had either a partial nephrectomy (38, 86%) or radical nephrectomy (six, 14%). The median (range) tumour size was 2.5 (0.6-19) cm. Perioperative complications occurred in 10 patients (23%), and a total of seven renal units (16%) were lost. Ten patients (23%) had chronic kidney disease (CKD) before surgery, while new onset CKD developed in six (14%) at the last follow-up. There were no recurrences and there was one unrelated death at a median follow-up of 28 months.
  
  
  CONCLUSIONS
  AML is a benign renal neoplasm that should be treated conservatively. Surgical intervention should be avoided, when possible, as it can lead to perioperative complications, loss of renal units, and development of CKD.
authors.affiliation: Urology Service, Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
authors.forename: Ryan K
authors.initials: RK
authors.lastname: Berglund
authors.forename: Melanie
authors.initials: M
authors.lastname: Bernstein
authors.forename: Martin T
authors.initials: MT
authors.lastname: Manion
authors.forename: Karim A
authors.initials: KA
authors.lastname: Touijer
authors.forename: Paul
authors.initials: P
authors.lastname: Russo
mesh_terms: D000328:Adult; D018207:Angiomyolipoma / Q000473:pathology / Q000601:surgery*; D002292:Carcinoma, Renal Cell / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D033162:Incidental Findings; D007680:Kidney Neoplasms / Q000473:pathology / Q000601:surgery*; D008297:Male; D009392:Nephrectomy / Q000009:adverse effects / Q000379:methods*; D011183:Postoperative Complications / Q000209:etiology* / Q000517:prevention & control; D012189:Retrospective Studies; D016896:Treatment Outcome