title: Differences Between Bilateral Adrenal Incidentalomas and Unilateral Lesions.
abstract: OBJECTIVE
  Adrenal incidentalomas are found in 1% to 5% of abdominal cross-sectional imaging studies. Although the workup and management of unilateral lesions are well established, limited information exists for bilateral incidentalomas.
  
  
  OBJECTIVE
  To compare the natural history of patients having bilateral incidentalomas with those having unilateral incidentalomas.
  
  
  METHODS
  Retrospective analysis of a prospective database of consecutive patients referred to an academic multidisciplinary adrenal conference. The setting was a tertiary care university hospital among a cohort of 500 patients with adrenal lesions between July 1, 2009, and July 1, 2014.
  
  
  METHODS
  Prevalence, age, imaging characteristics, biochemical workup, any intervention, and final diagnosis.
  
  
  RESULTS
  Twenty-three patients with bilateral incidentalomas and 112 patients with unilateral incidentalomas were identified. The mean age at diagnosis of bilateral lesions was 58.7 years. The mean lesion size was 2.4 cm on the right side and 2.8 cm on the left side. Bilateral incidentalomas were associated with a significantly higher prevalence of subclinical Cushing syndrome (21.7% [5 of 23] vs 6.2% [7 of 112]) (P = .009) and a significantly lower prevalence of pheochromocytoma (4.3% [1 of 23] vs 19.6% [22 of 112]) (P = .003) compared with unilateral lesions, while rates of hyperaldosteronism were similar in both groups (4.3% [1 of 23] vs 5.4% [6 of 112]) (P > .99). Only one patient with bilateral incidentalomas underwent unilateral resection. The mean follow-up was 4 years (range, 1.2-13.0 years). There were no occult adrenocortical carcinomas.
  
  
  CONCLUSIONS
  Bilateral incidentalomas are more likely to be associated with subclinical Cushing syndrome and less likely to be pheochromocytomas. Although patients with bilateral incidentalomas undergo a workup similar to that in patients with unilateral lesions, differences in their natural history warrant a greater index of suspicion for subclinical Cushing syndrome.
authors.affiliation: Section of Endocrine Surgery, Department of Surgery, University of California, San Francisco.
authors.forename: Jesse D
authors.initials: JD
authors.lastname: Pasternak
authors.affiliation: Section of Endocrine Surgery, Department of Surgery, University of California, San Francisco.
authors.forename: Carolyn D
authors.initials: CD
authors.lastname: Seib
authors.affiliation: Section of Endocrine Surgery, Department of Surgery, University of California, San Francisco.
authors.forename: Natalie
authors.initials: N
authors.lastname: Seiser
authors.affiliation: Division of Endocrinology, Department of Medicine, University of California, San Francisco.
authors.forename: J Blake
authors.initials: JB
authors.lastname: Tyrell
authors.affiliation: Division of Endocrinology, Department of Medicine, University of California, San Francisco.
authors.forename: Chienying
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Surgery, Good Samaritan Hospital, San Jose, California.
authors.forename: Robin M
authors.initials: RM
authors.lastname: Cisco
authors.affiliation: Section of Endocrine Surgery, Department of Surgery, University of California, San Francisco.
authors.forename: Jessica E
authors.initials: JE
authors.lastname: Gosnell
authors.affiliation: Section of Endocrine Surgery, Department of Surgery, University of California, San Francisco.
authors.forename: Wen T
authors.initials: WT
authors.lastname: Shen
authors.affiliation: Section of Endocrine Surgery, Department of Surgery, University of California, San Francisco.
authors.forename: Insoo
authors.initials: I
authors.lastname: Suh
authors.affiliation: Section of Endocrine Surgery, Department of Surgery, University of California, San Francisco.
authors.forename: Quan-Yang
authors.initials: QY
authors.lastname: Duh
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000175:diagnosis*; D003480:Cushing Syndrome / Q000175:diagnosis*; D005260:Female; D006801:Humans; D033162:Incidental Findings; D008297:Male; D008875:Middle Aged; D010673:Pheochromocytoma / Q000175:diagnosis*; D012189:Retrospective Studies