Adrenal incidentaloma--experience of a standardized diagnostic programme in the Swedish prospective study

J Intern Med. 2002 Sep;252(3):239-46. doi: 10.1046/j.1365-2796.2002.01028.x.


Objective: To report the 5-year experience of a diagnostic programme for adrenal incidentaloma with special emphasis to diagnose hormonally active and malignant lesions.

Design: A prospective study in which new cases of adrenal incidentalomas in Sweden have been evaluated by a standardized diagnostic protocol between January 1996 and July 2001.

Setting: Thirty-three different Swedish hospitals have contributed with cases.

Subjects: A total of 381 patients (217 females, 164 males) with adrenal incidentalomas were studied.

Interventions: Diagnostic procedures were undertaken according to a standardized programme. Operation was recommended if the incidentaloma had a size of more than 3-4 cm or if there was a suspicion of a hypersecreting tumour.

Main outcome measures: The size of the incidentaloma, clinical characteristics of the patients and results of biochemical diagnostic tests were registered.

Results: The median age of the patients was 64 years (18-84 years), and the median size of the incidentalomas was 3 cm (1-20 cm). A total of 85(22%) patients were operated. Twenty of these patients were diagnosed with a benign hypersecreting tumour and 14 with a malignant tumour. Fourteen of 15 operated patients with diagnosed pheochromocytoma had elevated 24-h urinary noradrenaline and all of the patients operated because of a biochemical suspicion of aldosterone or cortisol hypersecretion (n = 6) were found to have adrenal adenomas. Of the 14 operated patients with malignant diseases, 10 were adrenal carcinomas (median size 10 cm; range 4-16 cm). In a multiple logistic regression model, incidentaloma size was significantly associated with the risk of a malignant tumour (P = 0.009), and there was a tendency of an association between age/male sex and the risk of a malignancy (both, P = 0.07).

Conclusion: In this Swedish multicentre study of 381 cases with adrenal incidentalomas, 5% had benign hypersecreting tumours and nearly 4% had malignant tumours. The results of the biochemical diagnostic tests used had a high compatibility with the histological diagnosis found at operation in the patients with hypersecreting tumours. Tumour size, male gender and high age were predictive for the risk of a malignant tumour. A follow-up of the patients is warranted in order to establish whether there are undiscovered cases of malignant or hypersecreting tumours amongst the nonoperated patients.

Publication types

  • Clinical Trial
  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoma / blood
  • Adenoma / diagnosis*
  • Adenoma / surgery
  • Adolescent
  • Adrenal Gland Neoplasms / blood
  • Adrenal Gland Neoplasms / diagnosis*
  • Adrenal Gland Neoplasms / surgery
  • Adult
  • Age Factors
  • Aged
  • Aged, 80 and over
  • Biopsy
  • Carcinoma / blood
  • Carcinoma / diagnosis*
  • Carcinoma / surgery
  • Child
  • Diagnostic Techniques and Procedures / standards*
  • Diagnostic Techniques, Endocrine / standards
  • Disease Progression
  • Female
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Pheochromocytoma / blood
  • Pheochromocytoma / diagnosis*
  • Pheochromocytoma / surgery
  • Predictive Value of Tests
  • Prospective Studies
  • Sex Factors
  • Sweden
  • Tomography, X-Ray Computed