MDCT in the differentiation of adrenal masses: comparison between different scan delays for the evaluation of intralesional washout

Incidental, Solitary, and Unilateral Adrenal Metastasis as the Initial Manifestation of Lung Adenocarcinoma

An adrenal incidentaloma is an adrenal mass ≥ 1 cm in size discovered on imaging performed for indications other than suspected adrenal disease. It has variable etiologies, which can be benign or malignant, including primary or metastatic disease. We present a rare case of metastatic lung adenocarcinoma with isolated unilateral adrenal metastases, presenting as an adrenal incidentaloma in an asymptomatic patient with no known history of malignancy. A 76-year-old man with a past medical history of chronic obstructive pulmonary disease (COPD) and heavy tobacco use was admitted for the evaluation and treatment of pneumonia. He was found to have an incidental 4.6 cm unilateral adrenal mass on his CT chest. He underwent a workup for the mass, including further imaging studies that were indeterminate and a hormonal workup that concluded that the mass was nonfunctional. Due to the patient's comorbidities, it was determined that he was not a surgical candidate. A multidisciplinary team recommended a biopsy, which revealed metastatic lung adenocarcinoma. The primary lung cancer was located using positron emission tomography with 2-deoxy-2-(fluorine-18) fluoro-D-glucose combined with computed tomography (F-FDG-PET/CT). The patient was evaluated by an oncology service and started on chemotherapy. In this case report, we discuss the approach for evaluating adrenal incidentalomas as well as the role the biopsy has in this process based on a literature review. In addition, we draw a comparison between our case and similar cases in the literature while highlighting the differences that make this case unique.

A deep learning-based approach for the diagnosis of adrenal adenoma: a new trial using CT

OBJECTIVE

To develop and validate deep convolutional neural network (DCNN) models for the diagnosis of adrenal adenoma (AA) using CT.

METHODS

This retrospective study enrolled 112 patients who underwent abdominal CT (non-contrast, early, and delayed phases) with 107 adrenal lesions (83 AAs and 24 non-AAs) confirmed pathologically and with 8 lesions confirmed by follow-up as metastatic carcinomas. Three patients had adrenal lesions on both sides. We constructed six DCNN models from six types of input images for comparison: non-contrast images only (Model A), delayed phase images only (Model B), three phasic images merged into a 3-channel (Model C), relative washout rate (RWR) image maps only (Model D), non-contrast and RWR maps merged into a 2-channel (Model E), and delayed phase and RWR maps merged into a 2-channel (Model F). These input images were prepared manually with cropping and registration of CT images. Each DCNN model with six convolutional layers was trained with data augmentation and hyperparameter tuning. The optimal threshold values for binary classification were determined from the receiver-operating characteristic curve analyses. We adopted the nested cross-validation method, in which the outer fivefold cross-validation was used to assess the diagnostic performance of the models and the inner fivefold cross-validation was used to tune hyperparameters of the models.

RESULTS

The areas under the curve with 95% confidence intervals of Models A-F were 0.94 [0.90, 0.98], 0.80 [0.69, 0.89], 0.97 [0.94, 1.00], 0.92 [0.85, 0.97], 0.99 [0.97, 1.00] and 0.94 [0.86, 0.99], respectively. Model E showed high area under the curve greater than 0.95.

CONCLUSION

DCNN models may be a useful tool for the diagnosis of AA using CT.

ADVANCES IN KNOWLEDGE

The current study demonstrates a deep learning-based approach could differentiate adrenal adenoma from non-adenoma using multiphasic CT.

Qualitative Heterogeneous Signal Drop on Chemical Shift (CS) MR Imaging: Correlative Quantitative Analysis between CS Signal Intensity Index and Contrast Washout Parameters Using T1-Weighted Sequences

The aim of this study was to calculate MRI quantitative parameters extracted from chemical-shift (CS) and dynamic contrast-enhanced (DCE) T1-weighted (T1-WS) images of adrenal lesions (AL) with qualitative heterogeneous signal drop on CS T1-WS and compare them to those of AL with homogeneous or no signal drop on CS T1-WS. On 3 T MRI, 65 patients with a total of 72 AL were studied. CS images were qualitatively assessed for grouping AL as showing homogeneous (Group 1, n = 19), heterogeneous (Group 2, n = 23), and no (Group 3, n = 30) signal drop. Histopathology or follow-up data served as reference standard to classify AL. ROIs were drawn both on CS and DCE images to obtain adrenal CS signal intensity index (ASII), absolute (AWO), and relative washout (RWO) values. Quantitative parameters (QP) were compared with ANOVA analysis and post hoc Dunn’s test. The performance of QP to classify AL was assessed with receiver operating characteristic analysis. CS ASII values were significantly different among the three groups (p < 0.001) with median values of 71%, 53%, and 3%, respectively. AWO/RWO values were similar in Groups 1 (adenomas) and 2 (benign AL) but significantly (p < 0.001) lower in Group 3 (20 benign AL and 10 malignant AL). With cut-offs, respectively, of 60% (Group 1 vs. 2), 20% (Group 2 vs. 3), and 37% (Group 1 vs. 3), CS ASII showed areas under the curve of 0.85, 0.96, and 0.93 for the classification of AL, overall higher than AWO/RWO. In conclusion, AL with qualitative heterogeneous signal drop at CS represent benign AL with QP by DCE sequence similar to those of AL with homogeneous signal drop at CS, but different to those of AL with no signal drop at CS; ASII seems to be the only quantitative parameter able to differentiate AL among the three different groups.

Adrenal wash-out CT: moderate diagnostic value in distinguishing benign from malignant adrenal masses

OBJECTIVE

Reliable results of wash-out CT in the diagnostic workup of adrenal incidentalomas are scarce. Thus, we evaluated the diagnostic accuracy of delayed wash-out CT and determined thresholds to accurately differentiate adrenal masses.

DESIGN

Retrospective, single-center cohort study including 216 patients with 252 adrenal lesions who underwent delayed wash-out CT. Definitive diagnoses based on histopathology (n = 92) or comprehensive follow-up.

METHODS

Size, average attenuation values of the adrenal lesions in all CT scan phases, and absolute and relative percentage wash-out (APW/RPW) were determined by an expert radiologist blinded for clinical data. Adrenal lesions with unenhanced attenuation values >10 Hounsfield units (HU) built a subgroup (n = 142). Diagnostic accuracy was calculated.

RESULTS

The study group consisted of 171 adenomas, 32 other benign tumors, 11 pheochromocytomas, 9 adrenocortical carcinomas, and 29 other malignant tumors. All (potentially) malignant and 46% of benign lesions showed unenhanced attenuation values >10 HU. In this most relevant subgroup, the established thresholds of 60% for APW and 40% for RPW misclassified 35.9 and 35.2% of the masses, respectively. When we applied optimized cutoffs (APW >83%; RPW >58%) and excluded pheochromocytomas, we missed only one malignant tumor by APW and none by RPW. However, only 11 and 15% of the benign tumors were correctly identified.

CONCLUSIONS

Wash-out CT with the established thresholds for APW and RPW is insufficient to reliably diagnose adrenal masses. Using the proposed cutoff of 58% for RPW, malignant tumors will be correctly identified, but the added value is limited, namely 15% of patients with benign tumors can be prevented from additional imaging or even unnecessary surgery.

Adrenal incidentalomas: imaging challenges—role of MDCT scan versus MRI in evaluating adrenal incidentalomas

Background

The term adrenal incidentaloma (AI), by definition, is an adrenal mass that is unexpectedly detected through an imaging procedure performed for reasons unrelated to adrenal dysfunction or suspected dysfunction. Despite their frequent appearance, the challenge remains in recognizing and treating the small percentage of AI that poses a significant risk, either because of their hormonal activity or because of their malignant histology. The aim of this study is to study the role of MRI, specifically chemical shift imaging (CSI), against various MDCT scans (non-enhanced, enhanced, and delayed) in the characterization of incidentally discovered adrenal masses to offer a way for the patients to avoid unnecessary time and money-wasting imaging modalities used to reach a diagnosis of their incidentally discovered adrenal lesions. We examined a total number of 20 patients with total of 22 adrenal lesions. The mean age was 51.1 ± 15.27.

Results

In our study, we found that among CT parameters, APW and RPW showed the highest sensitivity and specificity for detection of lipid-rich adenomas. CSI has also proven to be the best MR technique. However, there is no statistically significant difference in the diagnostic capability of CSI versus the CT washout technique. Both modalities could be conducted, according to specific patient preferences and/or limitations, with comparable highly accurate outcomes.

Conclusion

This study demonstrates that a similar diagnostic outcome is obtained from contrast-enhanced CT (CECT) and MRI with CSI of adrenal lesions.

Computed tomography (CT) scan identified necrosis, but is it a reliable single parameter for discerning between malignant and benign adrenocortical tumors?

BACKGROUND

Adrenocortical carcinoma is a rare malignant tumor with a poor prognosis. Discernment of adrenocortical carcinoma in an adrenal mass through imaging studies is paramount for early surgical treatment. Recently, necrosis has been proposed as a single morphological parameter for adrenocortical carcinoma diagnosis. The aim of this study was to analyze the measures of diagnostic efficiency of necrosis and the different computed tomography-scan features related to adrenocortical carcinoma diagnosis.

METHODS

We conducted a case-control study of patients surgically treated for an adrenal mass with histopathological report consistent with adrenocortical carcinoma (cases) and adrenocortical adenoma (control patients) between 1987 and 2019. Radiological features on computed tomography scan were collected. Bivariate and multivariate statistical analyses were performed for the different imaging features. The measures of diagnostic efficiency for each feature were calculated. Concordance analysis between image-detected and histopathological-identified necrosis was performed.

RESULTS

Eighteen adrenocortical carcinoma and 41 adrenocortical adenomas were included. Differences between adrenocortical carcinoma and adrenocortical adenoma were found regarding heterogeneity (odds ratio 4.53, 95% confidence interval 2.3-8.9; P < .0001), tumor size ≥4 cm (odds ratio 3.5, 95% confidence interval 2.05-6.14; P < .0001), and attenuation index ≥10 Hounsfield units (odds ratio 1.9, 95% confidence interval 1.3-2.6; P = .001). Necrosis was the most important imaging feature significantly associated with adrenocortical carcinoma (odds ratio 35, 95% confidence interval 5.1-241.6; P < .0001), present in all adrenocortical carcinoma cases. After measures of diagnostic efficiency calculation, necrosis had the highest diagnostic accuracy (98%). Cohen's kappa for concordance between image-detected and histopathological-identified necrosis was 90.4% (P < .0001).

CONCLUSION

Computed tomography scan-detected necrosis is a reliable radiological feature to discern adrenocortical carcinoma from adrenocortical adenomas.

Adrenal Incidentaloma

An adrenal incidentaloma is now established as a common endocrine diagnosis that requires a multidisciplinary approach for effective management. The majority of patients can be reassured and discharged, but a personalized approach based upon image analysis, endocrine workup, and clinical symptoms and signs are required in every case. Adrenocortical carcinoma remains a real concern but is restricted to <2% of all cases. Functional adrenal incidentaloma lesions are commoner (but still probably <10% of total) and the greatest challenge remains the diagnosis and optimum management of autonomous cortisol secretion. Modern-day surgery has improved outcomes and novel radiological and urinary biomarkers will improve early detection and patient stratification in future years to come.

WFUMB position paper on the management incidental findings: adrenal incidentaloma

Focal lesions of the adrenal glands are incidentally detected in approximately 5% of cases by modern imaging techniques. Fewer than 5% of these adrenal incidentalomas are malignant and approximately 10% have endocrine activity. Reliable differentiation of malignant versus benign and hormonally active versus nonfunctional adrenal incidentalomas significantly influences therapeutic management and the outcome of affected individuals. Therefore, each adrenal incidentaloma should undergo a standardized diagnostic work-up to exclude malignancy and endocrine activity. This position statement of the World Federation of Ultrasound in Medicine and Biology (WFUMB) summarizes the available evidence on the management of adrenal incidentaloma and describes efficient management strategies with particular reference to the role of ultrasound techniques.

Diagnostic Accuracy of Computed Tomography to Exclude Pheochromocytoma: A Systematic Review, Meta-analysis, and Cost Analysis

OBJECTIVES

To assess the diagnostic accuracy of unenhanced computed tomography (CT) attenuation values to exclude a pheochromocytoma in the diagnostic work-up of patients with an adrenal incidentaloma and to model the associated difference in diagnostic costs.

METHODS

The MEDLINE and Embase databases were searched from indexing to September 27, 2018, and studies reporting the proportion of pheochromocytomas on either side of the 10-Hounsfield unit (HU) threshold on unenhanced CT were included. The pooled proportion of pheochromocytomas with an attenuation value greater than 10 HU was determined, as were the modeled financial costs of the current and alternative diagnostic approaches.

RESULTS

Of 2957 studies identified, 31 were included (N=1167 pheochromocytomas). Overall risk of bias was low. Heterogeneity was not observed between studies (Q=11.5, P=.99, I²=0%). The pooled proportion of patients with attenuation values greater than 10 HU was 0.990 (95% CI, 0.984-0.995). The modeled financial costs using the new diagnostic approach were €55 (∼$63) lower per patient.

CONCLUSION

Pheochromocytomas can be reliably ruled out in the case of an adrenal lesion with an unenhanced CT attenuation value of 10 HU or less. Therefore, determination of metanephrine levels can be restricted to adrenal tumors with an unenhanced CT attenuation value greater than 10 HU. Implementing this novel diagnostic strategy is cost-saving.

Distinguishing adrenal adenomas from non-adenomas with multidetector CT: evaluation of percentage washout values at a short time delay triphasic enhanced CT

OBJECTIVE:

To retrospectively evaluate the diagnostic values of absolute percentage washout ratio (APW) and relative percentage washout ratio (RPW) obtained from a short time delay triphasic enhanced CT in distinguishing adenomas from non-adenomas.

METHODS:

The study population consisted of 116 patients (58 males and 58 females; mean age, 52 years; age range, 23-89 years) with 116 adrenal masses from 2010 to 2016. Absolute attenuation values in each phase of CT were measured, and then the APW and RPW were calculated. The APW and RPW receiver operating characteristic (ROC) analysis was performed to evaluate the strength of the tests. Sensitivity, specificity, and accuracy were calculated for APW and RPW.

RESULTS:

Significant differences were observed in APW and RPW values between the adenoma and non-adenoma groups (p < 0.001). Areas under the ROC curve were 0.822 (95% confidence interval: 0.730, 0.914) and 0.913 (95% confidence interval: 0.851, 0.975) for the APW and RPW tests, respectively. The RPW (≥30%) criterion showed the best accuracy (86%), with 85% sensitivity and 90% specificity, followed by the APW (≥32%) criterion, with 81% accuracy, 85% sensitivity, and 69% specificity.

CONCLUSION:

The APW and RPW values from a short time delay triphasic enhanced CT were efficient and helpful in differentiating adenomas from non-adenomas, and could provide comparable diagnostic results to the previous reported longer delayed dedicated adrenal CT protocols.

ADVANCES IN KNOWLEDGE:

The washout ratio from a short time delay triphasic enhanced CT could help in differentiating adenomas from non-adenomas without the dedicated adrenal CT.

The role of dynamic post-contrast T1-w MRI sequence to characterize lipid-rich and lipid-poor adrenal adenomas in comparison to non-adenoma lesions: preliminary results

PURPOSE

The purpose of the article is to compare the features of wash-out (WO) parameters between lipid-rich and lipid-poor adrenal adenomas as well as with a group of non-adenoma adrenal lesions.

METHODS

46 patients (36 F and 10 M, median age 58 years) with unilateral adrenal lesions (35 adenomas, 7 pheochromocytomas, 1 carcinoma, and 3 metastases) were prospectively evaluated; adrenal lesions were divided into adenomas (Group 1) and non-adenomas (Group 2). MR imaging was performed with a 3-Tesla scanner using pre- and post-contrast dedicated sequences. On the basis of the evaluation of qualitative chemical-shift (CS) signal intensity (SI) loss, adrenal adenomas were, respectively, divided in Group 1A (n = 25) as lipid-rich and Group 1B (n = 10) as lipid-poor; non-adenoma adrenal lesions were grouped in Group 2 (n = 11). The following parameters were evaluated: size (mm), CS SI index (%), early (5 min), and delayed (10 min) Relative (R) and Absolute (A) WO values (%).

RESULTS

The comparison of AWO and RWO showed significant (p ≤ 0.05) differences between Group 1A and Groups 1B and 2, both using 5- and 10-min images for calculation; conversely, no differences in these dynamic parameters were found between Group 1B and 2; AWO and RWO values were significantly lower in adrenal lesions of Groups 1B and 2 compared to Group 1A, both using 5- and 10-min images for calculation.

CONCLUSIONS

The quantitative evaluation of WO parameters could not be used to characterize lipid-poor adrenal adenomas for which alternative imaging modalities are required.

Utility of Intermediate-Delay Washout CT Images for Differentiation of Malignant and Benign Adrenal Lesions: A Multivariate Analysis

OBJECTIVE

The objective of this study was to identify features that impact the diagnostic performance of intermediate-delay washout CT for distinguishing malignant from benign adrenal lesions.

MATERIALS AND METHODS

This retrospective study evaluated 127 pathologically proven adrenal lesions (82 malignant, 45 benign) in 126 patients who had undergone portal venous phase and intermediate-delay washout CT (1-3 minutes after portal venous phase) with or without unenhanced images. Unenhanced images were available for 103 lesions. Quantitatively, lesion CT attenuation on unenhanced (UA) and delayed (DL) images, absolute and relative percentage of enhancement washout (APEW and RPEW, respectively), descriptive CT features (lesion size, margin characteristics, heterogeneity or homogeneity, fat, calcification), patient demographics, and medical history were evaluated for association with lesion status using multiple logistic regression with stepwise model selection. Area under the ROC curve (A_z) was calculated from both univariate and multivariate analyses. The predictive diagnostic performance of multivariate evaluations was ascertained through cross-validation.

RESULTS

A_z for DL, APEW, RPEW, and UA was 0.751, 0.795, 0.829, and 0.839, respectively. Multivariate analyses yielded the following significant CT quantitative features and associated A_z when combined: RPEW and DL (A_z = 0.861) when unenhanced images were not available and APEW and UA (A_z = 0.889) when unenhanced images were available. Patient demographics and presence of a prior malignancy were additional significant factors, increasing A_z to 0.903 and 0.927, respectively. The combined predictive classifier, without and with UA available, yielded 85.7% and 87.3% accuracies with cross-validation, respectively.

CONCLUSION

When appropriately combined with other CT features, washout derived from intermediate-delay CT with or without additional clinical data has potential utility in differentiating malignant from benign adrenal lesions.

Characterization of adrenal lesions using MDCT wash-out parameters: diagnostic accuracy of several combinations of intermediate and delayed phases

PURPOSE

To evaluate the diagnostic accuracy of wash-out parameters calculated using multiple intermediate and delayed phases.

MATERIALS AND METHODS

This prospective study had institutional review board approval and informed consent was obtained from all patients. Between January 2012 and October 2016, 108 consecutive oncologic patients (59 males, 49 females, mean age 52.6 years; 129 diagnosed lesions) underwent multiphasic CT protocol including unenhanced (UE), arterial (AE), portal (PE), 5-min (DE-5) and the 15-min (DE-15) delayed phases of adrenal glands. All images were randomly reviewed in consensus by two radiologists experienced in abdominal CT, unaware of clinical or pathologic data. Location, size and density were recorded. Absolute wash-out, percentage wash-out (PWO) and percentage enhancement wash-out ratio were calculated. The thresholds yielding the best accuracy in differentiating adenomas from nonadenomas were retrospectively determined on the basis of ROC curves. The corresponding diagnostic accuracy values were calculated. Paired sample t test was used to assess differences among imaging parameters within subgroups. Student t test was applied to compare lesions between independent subgroups. p values ≤ 0.05 were considered significant.

RESULTS

The final diagnosis included 82 adenomas (62 lipid-rich and 20 lipid-poor) and 47 nonadenomas (42 metastases, 3 pheochromocytomas, 2 carcinomas). All the 62 lipid-rich adenomas were correctly diagnosed as benign lesions on the basis of their UE attenuation < 10 HU. The PEAK attenuation was achieved during AE phase for 51/129 lesions (39.5%) and at the time of PE phase in 78/129 lesions (60.5%). The best overall accuracy in diagnosing adenomas (97.6%; 126/129 lesions correctly diagnosed) was obtained using 40% threshold for calculating PWO from PEAK to DE-15 scan.

CONCLUSIONS

If only an intermediate phase is available, the 15-min delayed scan should be acquired to avoid any drop in diagnostic accuracy. The availability of two intermediate phase may be used to easy CT schedule by obviating the need to acquire a longer delayed phase.

Management of adrenal incidentalomas: European Society of Endocrinology Clinical Practice Guideline in collaboration with the European Network for the Study of Adrenal Tumors

: By definition, an adrenal incidentaloma is an asymptomatic adrenal mass detected on imaging not performed for suspected adrenal disease. In most cases, adrenal incidentalomas are nonfunctioning adrenocortical adenomas, but may also represent conditions requiring therapeutic intervention (e.g. adrenocortical carcinoma, pheochromocytoma, hormone-producing adenoma or metastasis). The purpose of this guideline is to provide clinicians with best possible evidence-based recommendations for clinical management of patients with adrenal incidentalomas based on the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system. We predefined four main clinical questions crucial for the management of adrenal incidentaloma patients, addressing these four with systematic literature searches: (A) How to assess risk of malignancy?; (B) How to define and manage low-level autonomous cortisol secretion, formerly called 'subclinical' Cushing's syndrome?; (C) Who should have surgical treatment and how should it be performed?; (D) What follow-up is indicated if the adrenal incidentaloma is not surgically removed? SELECTED RECOMMENDATIONS: (i) At the time of initial detection of an adrenal mass establishing whether the mass is benign or malignant is an important aim to avoid cumbersome and expensive follow-up imaging in those with benign disease. (ii) To exclude cortisol excess, a 1mg overnight dexamethasone suppression test should be performed (applying a cut-off value of serum cortisol ≤50nmol/L (1.8µg/dL)). (iii) For patients without clinical signs of overt Cushing's syndrome but serum cortisol levels post 1mg dexamethasone >138nmol/L (>5µg/dL), we propose the term 'autonomous cortisol secretion'. (iv) All patients with '(possible) autonomous cortisol' secretion should be screened for hypertension and type 2 diabetes mellitus, to ensure these are appropriately treated. (v) Surgical treatment should be considered in an individualized approach in patients with 'autonomous cortisol secretion' who also have comorbidities that are potentially related to cortisol excess. (vi) In principle, the appropriateness of surgical intervention should be guided by the likelihood of malignancy, the presence and degree of hormone excess, age, general health and patient preference. (vii) Surgery is not usually indicated in patients with an asymptomatic, nonfunctioning unilateral adrenal mass and obvious benign features on imaging studies. We provide guidance on which surgical approach should be considered for adrenal masses with radiological findings suspicious of malignancy. Furthermore, we offer recommendations for the follow-up of patients with adrenal incidentaloma who do not undergo adrenal surgery, for those with bilateral incidentalomas, for patients with extra-adrenal malignancy and adrenal masses and for young and elderly patients with adrenal incidentalomas.

MANAGEMENT OF ENDOCRINE DISEASE: Imaging for the diagnosis of malignancy in incidentally discovered adrenal masses: a systematic review and meta-analysis

OBJECTIVE

Adrenal masses are incidentally discovered in 5% of CT scans. In 2013/2014, 81 million CT examinations were undertaken in the USA and 5 million in the UK. However, uncertainty remains around the optimal imaging approach for diagnosing malignancy. We aimed to review the evidence on the accuracy of imaging tests for differentiating malignant from benign adrenal masses.

DESIGN

A systematic review and meta-analysis was conducted.

METHODS

We searched MEDLINE, EMBASE, Cochrane CENTRAL Register of Controlled Trials, Science Citation Index, Conference Proceedings Citation Index, and ZETOC (January 1990 to August 2015). We included studies evaluating the accuracy of CT, MRI, or (18)F-fluoro-deoxyglucose (FDG)-PET compared with an adequate histological or imaging-based follow-up reference standard.

RESULTS

We identified 37 studies suitable for inclusion, after screening 5469 references and 525 full-text articles. Studies evaluated the accuracy of CT (n=16), MRI (n=15), and FDG-PET (n=9) and were generally small and at high or unclear risk of bias. Only 19 studies were eligible for meta-analysis. Limited data suggest that CT density >10HU has high sensitivity for detection of adrenal malignancy in participants with no prior indication for adrenal imaging, that is, masses with ≤10HU are unlikely to be malignant. All other estimates of test performance are based on too small numbers.

CONCLUSIONS

Despite their widespread use in routine assessment, there is insufficient evidence for the diagnostic value of individual imaging tests in distinguishing benign from malignant adrenal masses. Future research is urgently needed and should include prospective test validation studies for imaging and novel diagnostic approaches alongside detailed health economics analysis.