The indeterminate adrenal mass in patients with cancer

Can Radiomics Provide Additional Diagnostic Value for Identifying Adrenal Lipid-Poor Adenomas From Non-Adenomas on Unenhanced CT?

Background

It is difficult for radiologists to differentiate adrenal lipid-poor adenomas from non-adenomas; nevertheless, this differentiation is important as the clinical interventions required are different for adrenal lipid-poor adenomas and non-adenomas.

Purpose

To develop an unenhanced computed tomography (CT)-based radiomics model for identifying adrenal lipid-poor adenomas to assist in clinical decision-making.

Materials and methods

Patients with adrenal lesions who underwent CT between January 2015 and August 2021 were retrospectively recruited from two independent institutions. Patients from institution 1 were randomly divided into training and test sets, while those from institution 2 were used as the external validation set. The unenhanced attenuation and tumor diameter were measured to build a conventional model. Radiomics features were extracted from unenhanced CT images, and selected features were used to build a radiomics model. A nomogram model combining the conventional and radiomic features was also constructed. All the models were developed in the training set and validated in the test and external validation sets. The diagnostic performance of the models for identifying adrenal lipid-poor adenomas was compared.

Results

A total of 292 patients with 141 adrenal lipid-poor adenomas and 151 non-adenomas were analyzed. Patients with adrenal lipid-poor adenomas tend to have lower unenhanced attenuation and smoother image textures. In the training set, the areas under the curve of the conventional, radiomic, and nomogram models were 0.94, 0.93, and 0.96, respectively. There was no difference in diagnostic performance between the conventional and nomogram models in all datasets (all p < 0.05).

Conclusions

Our unenhanced CT-based nomogram model could effectively distinguish adrenal lipid-poor adenomas. The diagnostic power of conventional unenhanced CT imaging features may be underestimated, and further exploration is worthy.

Development of a radiomics model to diagnose pheochromocytoma preoperatively: a multicenter study with prospective validation

Background

Preoperative diagnosis of pheochromocytoma (PHEO) accurately impacts preoperative preparation and surgical outcome in PHEO patients. Highly reliable model to diagnose PHEO is lacking. We aimed to develop a magnetic resonance imaging (MRI)-based radiomic-clinical model to distinguish PHEO from adrenal lesions.

Methods

In total, 305 patients with 309 adrenal lesions were included and divided into different sets. The least absolute shrinkage and selection operator (LASSO) regression model was used for data dimension reduction, feature selection, and radiomics signature building. In addition, a nomogram incorporating the obtained radiomics signature and selected clinical predictors was developed by using multivariable logistic regression analysis. The performance of the radiomic-clinical model was assessed with respect to its discrimination, calibration, and clinical usefulness.

Results

Seven radiomics features were selected among the 1301 features obtained as they could differentiate PHEOs from other adrenal lesions in the training (area under the curve [AUC], 0.887), internal validation (AUC, 0.880), and external validation cohorts (AUC, 0.807). Predictors contained in the individualized prediction nomogram included the radiomics signature and symptom number (symptoms include headache, palpitation, and diaphoresis). The training set yielded an AUC of 0.893 for the nomogram, which was confirmed in the internal and external validation sets with AUCs of 0.906 and 0.844, respectively. Decision curve analyses indicated the nomogram was clinically useful. In addition, 25 patients with 25 lesions were recruited for prospective validation, which yielded an AUC of 0.917 for the nomogram.

Conclusion

We propose a radiomic-based nomogram incorporating clinically useful signatures as an easy-to-use, predictive and individualized tool for PHEO diagnosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03233-w.

Nontraumatic adrenal hemorrhage: the adrenal stress

Bilateral adrenal hemorrhage is a rare condition, which is burdened by potentially life-threatening consequences related to the development of acute adrenal insufficiency. Despite treatment with stress-dose glucocorticoids, a mortality rate of 15% has been reported, which varies according to the severity of underlying predisposing illness and could be much more higher if the adrenal insufficiency is not promptly recognized. An early diagnosis is crucial, though, because of nonspecific clinical and laboratory findings, adrenal hemorrhage is rarely suspected. Therefore, imaging has a pivotal role for the diagnosis of this uncommon condition but, despite adrenal hematomas characteristically appear round or oval with peripheral fat stranding, their initial presentation could be ambiguous. The authors describe a case of postoperative bilateral adrenal hemorrhage initially presenting at computed tomography scan as thickening of both glands surrounded by fat stranding, which led to close monitoring of adrenal function before unequivocal hemorrhage developed.

Likelihood ratio of computed tomography characteristics for diagnosis of malignancy in adrenal incidentaloma: systematic review and meta-analysis

Purpose

To propose an evidence based diagnostic algorithm using mass characteristics to determine malignancy in patients with adrenal incidentaloma by CTscan.

Methods

A systematic review in Medline, Scopus, relevant reference books and desk searching was performed up to January 2016 with relevant reference checking. The summery estimates of sensitivity, specificity, positive and negative likelihood ratio of different characteristics were calculated in two groups of the articles investigating the cases without previous malignancy and the articles investigating the oncologic cases.

Results

Thirty six articles were included in this study. In the first group with no history of malignancy a positive and negative LR of 3.1 and 0.13 in 4 cm threshold and positive and negative LR of 2.85 and 0 in 10HU density were found. In the second group with history of malignancy positive and negative LR of 2.3 and 0.27 in 3 cm threshold and positive and negative LR of 3.6 and 0.08 in 20HU density were resulted.

Conclusion

The results retrieved in this study considering the limitations show that adrenal incidentaloma with a size less than 4 cm or a mass larger than 4 cm with density less than 10HU in the first group can be managed with imaging follow up. For masses larger than 4 cm with density more than 10HU another diagnostic procedure should be performed. In the second group an adrenal mass larger than 3 cm or less than 3 cm with density more than 20HU should go under operation. But masses smaller than 3 cm with less than 20HU density can be followed by imaging.

Radiographic Characteristics of Adrenal Masses in Oncologic Patients

BACKGROUND

We aimed to assess the usefulness of pre-contrast Hounsfield unit (HU) and mass size on computed tomography to differentiate adrenal mass found incidentally in oncologic patients.

METHODS

From 2000 to 2012, 131 oncologic patients with adrenal incidentaloma were reviewed retrospectively. Receiver operating characteristic (ROC) curves were applied to determine the optimal cut-off value of the mean HU and size for detecting adrenal metastasis.

RESULTS

The median age was 18 years, and 80 patients were male. The initial mass size was 18 mm, and 71 (54.2%) of these were on the left side. A bilateral adrenal mass was found in 11 patients (8.4%). Biochemically functional masses were observed in 9.2% of patients. Thirty-six out of 119 patients with nonfunctional masses underwent adrenalectomy, which revealed metastasis in 13. The primary cancers were lung cancer (n=4), renal cell carcinoma (n=2), lymphoma (n=2), hepatocellular carcinoma (n=2), breast cancer (n=1), and others (n=2). The area under the curve for the size and HU for clinically suspicious metastasis were 0.839 (95% confidence interval [CI], 0.761 to 0.900; P<0.001) and 0.959 (95% CI, 0.898 to 0.988; P<0.001), respectively. The cut-off value to distinguish between metastasis and benign masses were 22 mm for size and 20 for HU.

CONCLUSION

ROC curve results suggest that pre-contrast HU >20 can be used as a diagnostic reference to suggest metastasis in oncologic patients with adrenal masses.

Adrenal Mass in Patients who Underwent Abdominal Computed Tomography Examination

BACKGROUND

Adrenal masses are usually discovered incidentally (IAM) during abdominal computed tomography (CT).

AIMS

We aimed to describe the prevalence, management, and outcome of incidentally discovered adrenal mass on radiological investigation.

MATERIALS AND METHODS

A retrospective analysis was conducted to look for IAM identified by abdominal CT performed for other reasons between 2004 and 2008 and were followed for 4 years. IAM patients with known malignancy or clinically evident adrenal disease or overt disease originally missed due to insufficient clinical examination were excluded.

RESULTS

A total of 13,115 patients underwent abdominal CT, of which 136 were identified with adrenal mass (69 males and 67 females). Overall, 84 patients had benign IAM and six had primary adrenal carcinoma (all had tumor size ≥4 cm and five were males). Hormonal evaluation was performed in 80 cases, which revealed hypersecretion in 10 cases (six had Conn's syndrome and four had pheochromocytoma). Males had higher frequency of right-sided IAMs; whereas, left-sided IAM swere more common among females (P = 0.02). Seven patients underwent surgery and all were males (one Conn's syndrome, one pheochromocytoma, three primary adrenal adenocarcinoma, one benign nonfunctional adenoma, and one metastatic tumor). Only one patient died due to brain metastasis.

CONCLUSION

The overall prevalence of adrenal incidentaloma is 1% in Qatar. Unfortunately, hormonal evaluation, surgical referral, and follow-up are not appropriate in this study. Moreover, screening of IAM warrants more attention to rule out malignancy. This work could be of value as a local auditing for the current management.

Staging of lung cancer

Primary lung cancer is the leading cause of cancer mortality in the world. Thorough clinical staging of patients with lung cancer is important, because therapeutic options and management are to a considerable degree dependent on stage at presentation. Radiologic imaging is an essential component of clinical staging, including chest radiography in some cases, computed tomography, MRI, and PET. Multiplanar imaging modalities allow assessment of features that are important for surgical, oncologic, and radiation therapy planning, including size of the primary tumor, location and relationship to normal anatomic structures in the thorax, and existence of nodal and/or metastatic disease.

The prevalence and relevance of adrenal masses in patients with sporadic gastroenteropancreatic neuroendocrine tumours (GEP-NET)

OBJECTIVE

The widespread application of abdominal computerized tomography (CT) imaging has revealed that 0.98-4.0% of individuals harbour adrenal lesions (incidentalomas). There is, however, paucity of information regarding the prevalence of adrenal lesions in patients with gastroenteropancreatic neuroendocrine tumours (GEP-NETS). Purpose of this study was to estimate the prevalence of adrenal lesions in patients with GEP-NETS and identify their radiological features and clinical significance.

DESIGN

The prevalence of adrenal lesions was estimated retrospectively in 438 patients with GEP-NETS who underwent abdominal imaging. Secretory status and changes in size were documented during subsequent follow-up. MEN-1 patients and ectopic ACTH-secreting tumours were excluded.

RESULTS

Adrenal lesions were detected in 32 (8.4%) of 383 patients included. The majority (22 patients - 69%) were located at the left adrenal gland and the mean size was 23.6 mm. In two patients, one with a well and another with a poorly differentiated tumour, clinicopathological features suggested adrenal metastases. During a mean follow-up period of 69.5 months, no subsequent growth of any adrenal lesion was observed. Endocrine evaluation documented subclinical glucocorticoid hypersecretion in 4 cases (14%). The presence of adrenal lesions did not correlate to distant metastases, however, they were observed more frequently in patients with G3 tumours.

CONCLUSION

The prevalence of adrenal lesions in patients with GEP-NETs was found to be higher than the general population and mostly represent benign adrenal adenomas (except patients with G3 tumours). Nevertheless, individualized assessment of imaging characteristics should be still considered.

Intraindividual comparison of 123I-mIBG SPECT/MRI, 123I-mIBG SPECT/CT, and MRI for the detection of adrenal pheochromocytoma in patients with elevated urine or plasma catecholamines

PURPOSE

To determine the diagnostic performance of ¹²³I-metaiodobenzylguanidine (mIBG) SPECT/MRI fusion, ¹²³I-mIBG SPECT/CT and adrenal MRI for the detection of pheochromocytoma in patients with elevated urine or plasma catecholamines.

PATIENTS AND METHODS

Twenty-two consecutive patients underwent both a whole-body ¹²³I-mIBG scan with SPECT/CT of the adrenal region and MRI of the adrenal glands. Fused SPECT/MRI, SPECT/CT, and MRI scans were evaluated. Imaging results were analyzed both on a per-patient and on a per-lesion basis. Histopathology and/or clinical and radiological follow-up served as the reference standard.

RESULTS

Sixteen adrenal tumors were found in thirteen patients. On a per-lesion basis, SPECT/CT had a sensitivity of 87.5%, a specificity of 93.8%, and an overall accuracy of 92.5%. MRI had a sensitivity of 87.5%, a specificity of 96.9%, and an overall accuracy of 95.0%. On a per-patient basis, both SPECT/CT and MRI had a sensitivity of 85.7%, a specificity of 93.3%, and an overall accuracy of 90.9%. SPECT/CT was concordant with MRI in 81.8% of cases. SPECT/MRI fusion was superior to both SPECT/CT and MRI and had a sensitivity of 100% on both a per-lesion and a per-patient basis.

CONCLUSIONS

¹²³I-mIBG SPECT/MRI has the highest sensitivity and accuracy for the detection and localization of pheochromocytomas. SPECT/CT and MRI of the adrenal glands are equivalent diagnostic procedures. However, MRI offers the advantage of fully diagnostic assessment of adrenal lesions other than pheochromocytoma undetectable by ¹²³I-mIBG.

Adrenal neoplasms

Adenoma, myelolipoma, phaeochromocytoma, metastases, adrenocortical carcinoma, neuroblastoma, and lymphoma account for the majority of adrenal neoplasms that are encountered in clinical practice. A variety of imaging methods are available for evaluating adrenal lesions including ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and nuclear medicine techniques such as meta-iodobenzylguanidine (MIBG) scintigraphy and positron-emission tomography (PET). Lipid-sensitive imaging techniques such as unenhanced CT and chemical shift MRI enable detection and characterization of lipid-rich adenomas based on an unenhanced CT attenuation of ≤ 10 HU and signal loss on opposed-phase compared to in-phase T1-weighted images, respectively. In indeterminate cases, an adrenal CT washout study may differentiate adenomas (both lipid-rich and lipid-poor) from other adrenal neoplasms based on an absolute percentage washout of >60% and/or a relative percentage washout of >40%. This is based on the principle that adenomas show rapid contrast washout while most other adrenal neoplasms including malignant tumours show slow contrast washout instead. ¹⁸F-2-fluoro-2-deoxy-d-glucose-PET (¹⁸FDG-PET) imaging may differentiate benign from malignant adrenal neoplasms by demonstrating high tracer uptake in malignant neoplasms based on the increased glucose utilization and metabolic activity found in most of these malignancies. In this review, the multi-modality imaging appearances of adrenal neoplasms are discussed and illustrated. Key imaging findings that facilitate lesion characterization and differentiation are emphasized. Awareness of these imaging findings is essential for improving diagnostic confidence and for reducing misinterpretation errors.

Androgen- and estrogen-secreting adrenal cancers

Androgen-secreting adrenal cancers are extremely rare malignancies, accounting for only a tiny proportion of the total number of women presenting with signs of androgen excess. Estrogen-secreting adrenal cancers are rarer still. Understanding how these tumors work benefits from an appreciation of adrenal steroid biosynthesis, as it is said that secretion in cancers is an anarchic version of normal adrenal function. Selection of patients in whom we should have a high suspicion of a malignancy is vital, so that biochemical investigation and imaging is deployed appropriately. When an adrenal tumor is found to secrete androgens or estrogens to excess, it can be difficult to confirm that it is a cancer, as there is significant overlap in the secretory patterns and imaging appearances of benign and malignant disease. The most reliable indicator of malignancy in these tumors remains the presence of metastases. Treatment is essentially surgical, although the role of mitotane is one undergoing evaluation.

A multi-center study on the surgical management of metastatic disease to adrenal glands

BACKGROUND

In the management of adrenal lesions in oncological patients, many issues are still controversial: morphological signs of suspected malignancy, accuracy of imaging examinations, use of fine needle aspiration (FNA), and the role of laparoscopy. The present study attempts to address these questions through the evaluation of the management of adrenal metastases (AM) in a wide cohort of patients included in the Italian Register of Endoscopic Adrenal Surgery.

METHODS

In January 2009, all patients recorded on the Register were evaluated, on the basis of CT scan, MRI, and FNA. The diagnostic, surgical, and follow-up data of 95 patients with pre-operative AM diagnosis have been reviewed. On the basis of the fulfilled criteria three patterns were identified: "diagnostic", "suspect," and "non-diagnostic."

RESULTS

CT scan sensitivity was 41.5%/77.9% and specificity was 54.5%/90.9% for "diagnostic"/"diagnostic" + "suspect" examinations, respectively. MRI sensitivity was 15.7%/78.9% and specificity was non-determinate/83.3% for "diagnostic"/"diagnostic" + "suspect" exams, respectively. Sensitivity of FNA was 33.3%. About surgery, conversions rate was 16.6%; no mortality or re-operations were reported; complications rate was 10.7%; and no relation was noted between tumor size and surgical outcome. Mean survival was 32 months; 5-year survival was 23%, independent of AM size; survival for lung AM was similar to that of breast and kidney AM.

CONCLUSIONS

Laparoscopy for AM, in expert hand, seems to be a feasible and oncologically safe approach. Due to the unsatisfactory diagnostic accuracy for AM, every oncological patient with suspect adrenal lesions should be encouraged to undergo this surgical procedure.