title: Adrenal Imaging Features Predict Malignancy Better than Tumor Size.
abstract: BACKGROUND
  In adrenal tumors, size ≥ 4 cm has been an indication for adrenalectomy due to concern for malignancy. We compared mass size to imaging features (ImF) for accuracy in diagnosing adrenal malignancy.
  
  
  METHODS
  Data were retrieved for 112 consecutive patients who had adrenalectomy from January 2011 to August 2014. ImF was classified as nonbenign if HU > 10 on unenhanced CT scan or if loss of signal on out-of-phase imaging was absent on chemical-shift MRI. Indications for resection included hormonal hypersecretion, nonbenign ImF, and/or size ≥ 4 cm.
  
  
  RESULTS
  Of 113 resected adrenals, 37 % were functional. Histologic malignancy occurred in 18 % (20/113) and included 3 adrenocortical carcinomas (ACC), 1 epithelioid liposarcoma, 1 lymphoma, 1 malignant nerve sheath tumor, and 14 adrenal metastases. Patients with malignancies were older (mean age, 60 ± 13 vs. 51 ± 14 years, p = 0.01). Malignant tumors were larger on preoperative imaging (mean 5.3 ± 3.2 vs. 3.9 ± 2.4 cm, p = 0.03). All 20 malignant masses had nonbenign ImF. In predicting malignancy, the sensitivity, specificity, NPV, and PPV of nonbenign ImF was 100, 57, 100, and 33 %, respectively. Size ≥ 4 cm was less predictive with sensitivity, specificity, NPV, and PPV of 55, 61, 86, and 23 %, respectively. If size ≥ 4 cm had been used as the sole criterion for surgery, 45 % of malignancies (9/20) would have been missed including 8 metastases and an ACC.
  
  
  CONCLUSIONS
  In resected adrenal tumors, the presence of nonbenign ImF is more sensitive for malignancy than mass size (100 vs. 55 %) with equivalent specificity. Regardless of mass size, adrenalectomy should be strongly considered when non-benign ImF are present.
authors.affiliation: Division of Endocrine Surgery, Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Jenny Y
authors.initials: JY
authors.lastname: Yoo
authors.affiliation: Division of Endocrine Surgery, Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Kelly L
authors.initials: KL
authors.lastname: McCoy
authors.affiliation: Division of Endocrine Surgery, Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Sally E
authors.initials: SE
authors.lastname: Carty
authors.affiliation: Division of Endocrine Surgery, Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Stang
authors.affiliation: Division of Endocrine Surgery, Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Michaele J
authors.initials: MJ
authors.lastname: Armstrong
authors.affiliation: Division of Endocrine Surgery, Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Gina M
authors.initials: GM
authors.lastname: Howell
authors.affiliation: Division of Surgical Oncology, Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: David L
authors.initials: DL
authors.lastname: Bartlett
authors.affiliation: Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Mitchell E
authors.initials: ME
authors.lastname: Tublin
authors.affiliation: Division of Endocrine Surgery, Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA. yipl@upmc.edu.
authors.forename: Linwah
authors.initials: L
authors.lastname: Yip
mesh_terms: D000293:Adolescent; D000310:Adrenal Gland Neoplasms / Q000145:classification / Q000473:pathology* / Q000601:surgery; D000315:Adrenalectomy; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*; D047368:Tumor Burden; D055815:Young Adult