Endocrine Abstracts

Background: Adrenal incidentalomas (AI) are common and reported at frequencies of 2-10% at CT-scans of the abdomen. It is established that the number of diagnosed and investigated cases of AI have increased over the last decades. This increase is closely related to the development of modern radiology. General access of CT scanners with higher performance have led to an improved capacity and consequently more performed investigations. Other contributing factors are improved imaging technique with higher resolution images and other effects that can enhance the possibility to detect adrenal masses. Increased knowledge and attendance of AI among radiologists are other important factors that probably also entail a more structured and clear reporting of the findings, which increases the likelihood that the diagnosis is recorded and that an adequate investigation is conducted.

Aim: To describe the development of the absolute numbers in relation to frequency of AI diagnosed with CT abdomen 2002 and 2015 in Regional Sweden.

Method: Retrospectively we reviewed all digital imaging reports of CT-scans of the abdomen performed on patients > 18 years at four hospitals in Regional Sweden in 2002 and 2015. To identify missed cases, images were reviewed if the adrenals were not mentioned in the report. Adrenal masses were subdivided into three classes, AI > 10 mm (according to regening definition of AI; adenoma >10 mm), hyperplasia/ general enlargement and suspected malignancy (metastasises/ adrenocortical cancer).

Results: 3467 imaging reports from 2939 individuals performed in 2002 were reviewed. In 2015 > 14000 investigations were performed, of which 5434 CT-scans of 5018 individuals were reviewed (only first 5 months in 2015). The median age in 2002 was 64 years (18–97) and in 2015 66 years (18–101). Adrenal masses were found in 3.0% in 2002 and 4.9% in 2015 (P < 0.05). 0.6% respectively 0.3% were classified as metastasises. The incidence of AI according to reigning definition (> 10 mm) was 2.0 resp 4.1% (P < 0.05).

Conclusion: A fourfold increase of performed investigations was observed comparing 2002 to 2015. Consequently, there was an increase of the absolute number of diagnosed AI. In parallel the incidence increased significant from 2.0 to 4.1%, which is relatively low in relation to reports from other cohorts. A direct comparison is though difficult to make due to differences in definition of adrenal masses and the types of CT exams used. The increased incidence is probably an effect of improved image technique in combination with enhanced awareness of AI among radiologists.