The incidental nonhyperfunctioning adrenal mass: an imaging algorithm for characterization

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.

Imaging of adrenal incidentaloma: our experience

PURPOSE

To investigate clinical, biochemical and radiological features in 35 patients with adrenal incidentaloma found on CT and/or MRI and to define the management of patients with adrenal masses.

MATHERIAL AND METHODS

From January 2011 and May 2013, 35 patients (19F, 16M) with an adrenal mass incidentally discovered on CT and/or MRI were enrolled in a retrospective study. Thirthy-two patients underwent MDCT and eight 1.5 MRI.

RESULTS

Patients consisted in 16 males and 19 females, aged between 25 and 89 yo. Adrenal lesions were most commonly found in the sixth decade; in relation to the side of the mass, 20 were found on left side, 15 on the right. Of all the mass analyzed, 3 were <1 cm diameter, 29 between 1 and 4 cm, 3 > 4 cm. The most common finding on CT was adenoma-like appearance (19 cases in relation to size, 14 in relation to attenuation values). Hormonal analysis showed 32 cases of nonfunctional masses and 3 cases of hormone activity. Adrenalectomy was performed in ten patients having adenoma (5 cases), malignant lesions (2 cases), pheocromocitoma, cyst and myelolipoma (1 case).

CONCLUSION

Diagnostic approach to adrenal incidentaloma is focused on the definition of malignancy and hormonal activity; the characterization is needs hormonal and radiological (CT and/or MRI) evaluation, even if a fine needle aspiration is needed in selected cases. Benign and/or non-hypersecreting hormone lesion with <4 cm diameter could be sent to follow-up; active adrenal tumors or >4 cm diameter lesions with malignancy suspicious or growth during follow-up could be treated with surgical adrenalectomy.

Differentiation between tuberculosis and primary tumors in the adrenal gland: evaluation with contrast-enhanced CT

The aim of the present study is to determine imaging criteria for differentiating tuberculosis from primary tumors in the adrenal gland on contrast-enhanced CT. Non-contrast and contrast-enhanced CT features in 108 patients with adrenal tuberculosis (n = 34) and primary tumor (n = 74) were retrospectively assessed for the location, size, calcification and enhancement patterns. The primary tumors included 41 adenomas, 11 pheochromocytomas, 4 carcinomas, 3 lymphomas, 6 myelolipomas, 6 ganglioneuromas, 2 neurilemmomas and 1 ganglioneuroblastoma. Biochemical investigation was performed for all patients. Of the tuberculosis cases, 31 (91%) invaded with bilateral involvement, while 7 (9%) of the primary tumors invaded with bilateral involvement (P < 0.001). Tuberculosis often showed calcification (20 of 34; 59%), whereas primary tumors infrequently showed calcification (6 of 74; 8%; P < 0.001). Low attenuation in the center with peripheral rim enhancement was more commonly seen in tuberculosis (16 of 34; 47%) than in primary tumors (7 of 74; 9%; P < 0.001). In the determination of tuberculosis, the highest sensitivity (91%) and accuracy (91%) were obtained with bilateral involvement, and the highest specificity (99%) was obtained with the contour preserved. In the determination of primary tumors using a combination of having unilateral involvement and being mass-like, the outcome was a sensitivity of 91%, specificity of 94% and accuracy of 92%. CT findings can differentiate tuberculosis from a primary tumor of the adrenal glands with high sensitivity and an acceptable specificity when combined with the endocrinological examination.

Clinical study of adrenal incidentaloma in Korea

BACKGROUND

This study was designed to evaluate the clinical, endocrinological and histological characteristics of adrenal incidentalomas.

METHODS

Eighty patients (41, males; 38, females; age range 17-80 years) who were diagnosed with adrenal incidentaloma at Korea University Hospital from 1992 to 2003 were studied retrospectively.

RESULTS

Endocrinological investigation revealed 16 pheochromocytomas (20%), nine Cushing's syndromes (11%), eight primary aldosteronism (10%) and 46 non-functioning tumors (58%). Forty-four patients received operations, and biopsies were performed on two patients. Pathologic examination revealed 16 adrenocortical adenomas (20%), five carcinomas (6%), 13 pheochromocytomas (16%), three metastatic cancers (4%), and other tumors (10%). The diameter of the carcinomas (mean: 10.8 cm, range: 5-19 cm) were significantly larger than the diameter of benign adenomas (mean: 2.84 cm, range: 1-6 cm) (p=0.002). According to the receiver operating charactenstic (ROC) curve analysis, the cut-off value of tumor size for discriminate malignant tumor was 4.75 cm (sensitivity 90%, specificity 58%). Twenty-four patients with non-functioning tumors were followed up for a period of 3 to 72 months. During the follow up period, two patients showed an increase in tumor size of more than 1 cm, and one patient developed Cushing's syndrome. Changes in mass size and function were observed only between 10 and 26 months after the initial diagnosis.

CONCLUSIONS

These data show that an endocrine evaluation should be performed in all adrenal incidentalomas, and an adrenalectomy is recommended for tumors 5 cm or greater or tumors with adrenocortical hyperfunction. In addition, these tumors should be monitored for changes in mass size and function for a follow up period of approximately 26 months.

Magnetic Resonance Imaging of the Adrenal Glands

Differentiation of pathologic alterations of the adrenal glands is still a frequent and challenging problem of daily practice in radiology. Two main groups of patients have to be differentiated: those with clinical symptoms, mainly of endocrinopathies, and those in which a mass of the adrenal gland is detected incidentally. In the first group, magnetic resonance imaging (MRI) plays a minor role, although it allows to detect and often even differentiate the cause of the disease. In the second group, MRI has an excellent performance in differentiating between adenomas and non-adenomatous lesions of the adrenal glands.

Evaluation of the incidentally discovered adrenal mass

The increased use of abdominal ultrasonography, computed tomography, and magnetic resonance imaging has led to the classification of adrenal lesions termed the incidentally identified adrenal mass or adrenal incidentaloma. Unlike for the large, clinically, or biochemically symptomatic adrenal mass, the evaluation of patients with small, asymptomatic, or nonfunctional adrenal lesions remains controversial. The evaluation of these adrenal incidentalomas presents a challenge to endocrinologists, radiologists, and urologic surgeons alike. A multidisciplinary approach with biochemical screening and radiologic evaluation is essential to assess the nature and function of these lesions. Furthermore, it is of great importance to identify patients who are morbidly affected by hormonal hypersecretion or malignant potential. This article describes the emerging guidelines for the evaluation of the incidental adrenal mass.

[Non-secreting adrenal tumours]

This paper presents the clinical features, imaging methods and treatment of non-secreting adrenal tumours. Adrenal incidentalomas are especially discussed. The main histological types of adrenal non-secreting tumours are evoked. Therapeutic considerations are discussed.

Extra-thoracic staging of lung cancer

This article reviews the staging of extra-thoracic metastatic lung cancer. The imaging strategy, including when to screen as well as the different modalities available for different sites of spread of disease are discussed. The emerging role of whole body positron emission tomography in screening for metastases is also explored.

State of the art in adrenal imaging

The purposes of this article were to outline the current state of adrenal imaging, to highlight new developments, and to review the current radiologic advances that provide improved functional and structural information about adrenal disorders.

Radiologic characterization of adrenal masses: the role of computed tomography--derived attenuation values

BACKGROUND

Recent studies suggest that low computed tomography (CT) attenuation values can be used to differentiate benign adrenal adenomas from non-adenomas. We examined the utility of non-enhanced CT attenuation values of <or=10 Hounsfield units (HU) in differentiating adrenal adenomas from non-adenomas.

METHODS

During a 25-month period, patients who underwent adrenalectomy for adrenal masses visualized on abdominal CT were evaluated. Histopathologic examination of the excised adrenal mass was the gold standard for diagnosis. Patients who have undergone contrast-enhanced CT and those with bilateral adrenal masses were excluded. Statistical analysis was performed with the Student t test.

RESULTS

Fourteen patients met study criteria. Seven adenomas and 7 non-adenomas were identified. Mean CT attenuation values were 29 +/- 18 HU. There were no differences in age or tumor weight and size between groups. Adrenal adenomas had significantly lower attenuation values compared with non-adenomas, 17 +/- 14 HU versus 43 +/- 11 HU, (P < .05). The sensitivity-to-specificity ratio for diagnosing an adrenal adenoma was 43%:100%, whereas the positive and negative predictive values were 100% and 64%, respectively. All adrenal masses with attenuation values of <or=10 HU were adenomas.

CONCLUSIONS

The attenuation value of <or=10 HU on non-enhanced CT correctly identifies adrenal adenomas and is highly predictive of the diagnosis of adenoma.

Bilateral massive adrenal hemorrhage. Assessment of putative risk factors by the case-control method

Case reports and case series have identified putative risk factors for the development of bilateral massive adrenal hemorrhage (BMAH) in humans. The anatomy and physiology of the adrenal gland allow development of a model to fit the pathophysiology behind these risk factors. Until now, these risk factors were not systematically tested using analytical epidemiologic studies. A case-control study was undertaken using sources of cases and controls from multiple teaching hospitals in Ontario, Canada. The results of multivariate logistic regression indicated that thrombocytopenia (odds ratio [OR] = 14.6, 95% confidence intervals [CI] = 3.0-70.1, p < 0.001), heparin exposure of any route or type beyond 3 days (4-6 days: OR = 17.0, CI = 1.9-154.6; > 6 days: OR = 33.5, CI = 4.3-262.6; p < 0.001), and sepsis (OR = 6.3, CI = 1.2-32.2, p = 0.019) were most strongly and independently associated with development of BMAH. Another weaker positive association included invasive radiologic procedure (OR = 4.4, CI = 0.9-22.1, p = 0.055). Neither major surgery or duration of hospitalization were independent risk factors. Although coronary artery disease and possibly diabetes and hypertension appeared to be markers for lower risk of BMAH, this may be a result of bias introduced by using hospital controls ("Berkson bias"), as the effect was not explained by a protective effect of vasoactive medications. Thus, a picture of the high-risk patient should include a patient who has been treated with heparin (any route or type) beyond 3 days and has had thrombocytopenia (not necessarily induced by heparin) during the course of an illness. If the setting includes unexplained abdominal, chest, or back pain; fever; confusion; hypotension or shock; abrupt anemia; or electrolyte disorders, clinicians should not hesitate to cover empirically with lifesaving glucocorticoids while awaiting results of confirmatory tests.

Adrenal incidentaloma

Incidentally discovered adrenal masses, or adrenal incidentalomas, have become a common clinical problem owing to wide application of radiologic imaging techniques. This definition encompasses a heterogeneous spectrum of pathologic entities, including primary adrenocortical and medullary tumors, benign or malignant lesions, hormonally active or inactive lesions, metastases, and infections. Once an adrenal mass is detected, the clinician needs to address two crucial questions: is the mass malignant, and is it hormonally active? This article provides an overview of the diagnostic clinical approach and management of the adrenal incidentaloma. Mass size is the most reliable variable to distinguish benign and malignant adrenal masses. Adrenalectomy should be recommended for masses greater than 4.0 cm because of the increased risk of malignancy. Adrenal scintigraphy has proved useful in discriminating between benign and malignant lesions. Finally, fine-needle aspiration biopsy is an important tool in the evaluation of oncological patients and it may be useful in establishing the presence of metastatic disease. The majority of adrenal incidentalomas are non-hypersecretory cortical adenomas but an endocrine evaluation can lead to the identification of a significant number of cases with subclinical Cushing's syndrome (5-15%), pheochromocytoma (1.5-13%) and aldosteronoma (0-7%). The first step of hormonal screening should include an overnight low dose dexamethasone suppression test, the measure of urinary catecholamines or metanephrines, serum potassium and, in hypertensive patients, upright plasma aldosterone/plasma renin activity ratio. Dehydroepiandrosterone sulfate measurement may show evidence of adrenal androgen excess.

Management approaches to adrenal incidentalomas. A view from Rochester, Minnesota

Two biproducts of the revolution in diagnostic imaging techniques are unintended discoveries, and uncertainty for the patient and the clinician. To address the uncertainty associated with adrenal incidentalomas, clinicians need to understand the definition, differential diagnosis, and options for assessment with respect to functional status and malignancy potential. This article presents an algorithmic approach that addresses these issues.

Management approaches to adrenal incidentalomas. A view from Ancona, Italy

The definition of adrenal incidentaloma encompasses a heterogeneous spectrum of pathologic entities, including primary adrenocortical and medullary tumors, benign or malignant lesions, hormonally active or inactive lesions, metastases, and infections. This article provides an overview of the diagnostic clinical approach and management of the incidentally discovered adrenal masses. Approaches are based on data collected in more than 1000 cases of the Collaborative Study Group on Adrenal Incidentaloma of the Italian Society of Endocrinology and the authors' experience.