What is the role of ultrasonography in the follow-up of adrenal incidentalomas? The Gruppo Piemontese Incidentalomi Surrenalici

A step by step approach in differential diagnosing of adrenal incidentaloma (epinephroma), (with comments on the new Clinical Practice Guidelines of the European Society of Endocrinology)

Objectives. To present a step by step approach for the diagnosis of adrenal incidentaloma (AI).

Method. An extensive review of the literature was conducted, searching the Pub-Med and Google Scholar using the Mesh terms; Adrenal; Incidentaloma; Adrenal tumours; Radiology; Diagnosis. We also did a cross-referencing search of the literature. Comments on the new European guidelines are presented.

Results. The majority of the tumours are non-functioning benign adenomas. The most important radiological characteristic of an adrenal incidentaloma is the radiation attenuation coefficient. Wash out percentage and the imaging characteristics of the tumour may help in diagnosis.

Conclusion. Density less than 10 HU is in most cases characteristic of a lipid rich benign adenoma. More than 10 HU or/and history of malignancy raise the possibility for cancer. 1 mg dexamethasone test and plasma metanephrines should be done in all patients. If there is history of hypokalemia and/or resistant hypertension we test the plasma aldosterone to plasma renin ratio (ARR). Newer studies have shown that tumours even nonfunctioning and less than 4 cm may increase the metabolic risks so we may consider surgery at an earlier stage.

Radiology of the adrenal incidentalomas. Review of the literature

The term "adrenal incidentaloma" is a radiological term. Adrenal incidentalomas are adrenal tumors discovered in an imaging study that has been obtained for indications exclusive to adrenal conditions (Udelsman 2001; Linos 2003; Bulow et al. 2006; Anagnostis et al. 2009). This definition excludes patients undergoing imaging testing as part of staging and work-up for cancer (Grumbach et al. 2003; Anagnostis et al. 2009). Papierska et al. (2013) have added the prerequisite that the size of a tumor must be "greater than 1cm in diameter", in order to be called incidentaloma. Although in the most cases these masses are non-hypersecreting and benign, they still represent an important clinical concern because of the risk of malignancy or hormone hyperfunction (Barzon et al. 2003). Th e adrenal tumors belong to the commonest incidental findings having been discovered (Kanagarajah et al. 2012).

Advances in our understanding of the prognosis of adrenal incidentaloma

As cross-sectional abdominal imaging is used increasingly, adrenal incidentaloma (AI) are being found frequently and present a clinical dilemma. The vast majority are benign and non-functioning, but a minority represent incidentally found functional or malignant tumours. In this review we summarise the current clinical, biochemical and radiological investigation of AI and discuss recent advances that differentiate clinically inconsequential lesions from functional and/or malignant AI. Areas covered: Prevalence, natural history, biochemical and radiological assessment, indications for surgery and surgical provision. Expert commentary: Well established work-up of AI usually enables benign, non-functioning lesions to be differentiated from functioning and/or malignant AI. In indeterminate lesions recent advances in work-up such as urine steroid profiles measured by gas chromatography /mass spectrometry and functional imaging with 18F-Fluorodeoxyglucose (FDG) positron emission tomography (PET) in addition to standard investigations have improved characterisation of these lesions. The management of AI showing mild autonomous hypercortisolism without overt features of Cushing's syndrome remains controversial and is discussed in this review.

Adrenal incidentaloma: evaluation and management

Adrenal incidentalomas are adrenal masses discovered incidental to imaging studies performed for reasons unrelated to adrenal pathology. Although most adrenal incidentalomas are non-functioning benign adenomas, their increasing prevalence presents diagnostic and therapeutic challenges. The assessment of adrenal incidentalomas is aimed at deciding whether or not the tumour should be surgically removed. Adrenalectomy is indicated for phaeochromocytoma, other symptomatic hormone-secreting tumours and those with a high risk of malignancy. Biochemical screening for tumour hypersecretion is mandatory in all adrenal incidentalomas, since hormone secreting tumours may be clinically silent. The diagnosis of phaeochromocytoma is of paramount importance because of its life-threatening complications. Non-functioning adrenal incidentalomas need assessment for risk of malignancy, and this is based on the size of the tumour and its imaging characteristics. An observational policy with periodic radiological and biochemical reassessment is pursued in patients with non-functioning incidentalomas with low malignancy risk. The duration and frequency of reassessment remains unclear, as the natural history of adrenal incidentalomas has yet to be clearly defined, and there is a lack of controlled studies comparing surgical intervention with observation. However, the possibility of acquiring autonomous hypersecretion or conversion to malignancy in an incidentaloma diagnosed to be a benign non-functioning lesion is very low, and most patients may be safely discharged after an initial follow-up period of 2 years.

The diagnosis and treatment of primary adrenal lipomatous tumours in Chinese patients: A 31-year follow-up study

INTRODUCTION

Adrenal lipomatous tumours (ALTs) are rarely encountered in clinical practice and consequently little is known about their clinical features.

METHODS

We analyze the clinical features, diagnosis and treatment of ALTs based on cases presenting at a single centre over a 31-year period. We reviewed clinical data from patients with primary adrenal tumours treated at the Ruijin Hospital, Shanghai between January 1980 and December 2010.

RESULTS

A total of 73 cases of primary ALTs in 22 men and 51 women (mean age 51.1±14.2 years) were reviewed. The ALTs included 65 myelolipomas (89.0%), 3 lipomas (4.1%), 2 angiomyolipomas (2.7%), 2 teratomas (2.7%), and 1 liposarcoma (1.4%). Of the total 73 patients, 24 of them had tumours in the left adrenal gland, 47 in the right gland and 2 had bilateral tumours. In total, 51 patients underwent open surgery and 22 laparoscopic surgery.

CONCLUSION

Myelolipoma is predominant among the various types of lipomatous adrenal gland tumours; it accounts for about 90% of all cases. Surgery is recommended for tumours ≥3.5 cm in diameter, for all cases of symptomatic tumour, and for cases of teratoma or liposarcoma identified by preoperative imaging.

The washout rate on the delayed CT image as a diagnostic tool for adrenal adenoma verified by pathology: a multicenter study

OBJECTIVES

To establish the undisputed the value of washout rate for adrenal adenoma using delayed enhanced CT, we evaluated diagnostic performance of cut-off value and delayed time of washout rate by final pathologic diagnosis in a multicenter study.

METHODS

We reviewed the pathologic and clinical records of 244 patients underwent adrenalectomies at 5 university hospitals between 2005 and 2009. We calculated the mean Housfield units (HU) of adrenal lesion at non-enhancing CT, and early and delayed enhanced CT using the region of interest. We used ROC curves to determine the specificity and sensitivity of non-enhanced CT scans and the washout rate according to the various cut-off for adrenal adenomas.

RESULTS

We divided the patients into adrenal adenoma group (n = 138) and non-adrenal adenoma group (n = 106) based on final pathologic report. Using the unenhanced images with a threshold of 10 HU, the sensitivity was 45.7 %, and the specificity was 97.1 %. Using the 15-min-washout rate with a threshold of 55 %, the sensitivity was 93.9 %, and the specificity was 95.8 %.

CONCLUSIONS

Regardless of various CT machines and protocols, a washout rate of 15-min-delayed CT was most useful in the diagnosis of adrenal adenomas due to the early inflow and outflow of contrast media in the tissues of adrenal adenomas.

Adrenal incidentalomas

The term adrenal incidentaloma (AI) is usually defined as an adrenal mass unexpectedly detected through an imaging procedure performed for reasons a priori unrelated to adrenal dysfunction or suspected dysfunction. The preferred approach to their management in terms of diagnosis, follow-up, and treatment remain controversial despite a state-of-the-science conference sponsored by the U.S. National Institutes of Health. Although most experts' recommendations tend to be relatively minor variations of the conference's approach, dissenting voices have been heard. Despite their frequent appearance, the challenge remains to recognize and treat the small percentage of AI that do pose a significant risk, either because of their hormonal activity or because of their malignant histology, while leaving the rest alone. Although the differential diagnosis of an incidentally discovered mass is quite extensive, most AIs are non-secreting cortical adenomas. The noninvasive differentiation of benign and malignant lesions depends upon imaging characteristics, and sometimes radiologic diagnosis can be definitive, but often it is not, Among function lesions, autonomous cortisol production seems to be the most common and may be associated with increased cardiovascular risk and clinical features of the "metabolic syndrome." Follow-up of cases in which a specific diagnosis is not made initially involves assessment for growth and development of hormonal function, but even here, controversy about the extent of evaluation persists.

Adrenal disorders in pregnancy

Adrenal disorders may manifest during pregnancy de novo, or before pregnancy undiagnosed or diagnosed and treated. Adrenal disorders may present as hormonal hypofunction or hyperfunction, or with mass effects or other nonendocrine effects. Pregnancy presents special problems in the evaluation of the hypothalamic-pituitary-adrenal axis in addition to the usual considerations. The renin-angiotensin-aldosterone axis undergoes major changes during pregnancy. Nevertheless, the common adrenal disorders are associated with morbidity during pregnancy and their management is more complicated. A high index of suspicion must be maintained for these disorders lest they go unrecognized and untreated.

Management of adrenal incidentaloma

The term adrenal incidentaloma covers a wide spectrum of adrenal pathologies sharing the method of discovery. The management of adrenal incidentaloma is controversial, and clinicians should determine whether the patient's health is affected by the presence of a tumor. Critical points in management include differentiating benign from malignant and hormonally active from nonfunctional adrenal masses. The probability of malignancy is related to tumor size and imaging phenotype. Masses smaller than 4 cm in diameter that exhibit low attenuation by unenhanced CT scan and rapid contrast washout by delayed contrast-enhanced CT scan are probably benign. All patients with adrenal incidentaloma should undergo biochemical evaluations for pheochromocytoma and subclinical or overt Cushing's syndrome, and hypertensive patients should undergo biochemical testing for hyperaldosteronism. Laparoscopic adrenalectomy is the treatment of choice in all hypersecretory tumors. If adrenocortical carcinoma is suspected, an open adrenalectomy is recommended. Patients who are not candidates for surgical resection of the tumor should be monitored radiographically for 2 years, and hormonal follow-up should be performed annually for 4 years.

Adrenal incidentaloma in pregnancy: clinical, molecular and immunohistochemical findings

Adrenal incidentalomas detected during pregnancy are very rare, and the natural history of these tumors during gestation is unknown. We report a case of a pregnant woman with an adrenal mass discovered serendipitously, who was followed-up during gestation and underwent adrenalectomy shortly after delivery. This allowed the evaluation of both the clinical outcome and the molecular/immunohistochemical correlates. Estrogens may indeed influence the function and proliferation of human adrenal cells, and a state of circulating estrogen excess can represent an in vivo model to test their effect on the adrenals. No evidence of adrenal change in morphology and function was found in our patient throughout pregnancy, as shown by adrenal ultrasound imaging and adrenal hormone measurements. Four months after delivery, the patient underwent laparoscopic right adrenalectomy, and pathologic analysis revealed a 2.7 cm benign adrenocortical adenoma. The diameter of the adrenal mass at ultrasonography correlated highly with post-partum mass diameter measured by abdominal computed tomography (CT). Quantitative expression of both ERalpha and ERbeta by real-time RT-PCR analysis and Western blotting findings did not differ among adenoma, normal adjacent adrenal and normal adrenal control tissues. This case of an adrenal incidentaloma discovered during pregnancy shows that a close observation with endocrine investigations and ultrasonography could be an appropriate approach, delaying the decision of surgical intervention after delivery. Estrogen receptor mRNA levels in the adrenal mass similar to those observed in normal adrenals suggest that estrogen oversecretion during pregnancy was not a risk factor for tumor progression.

Importance of adrenal incidentaloma in patients with a history of malignancy

BACKGROUND

Adrenal incidentaloma presents a frequent finding in patients with a history of malignancy. This study was carried out to determine whether imaging techniques can discriminate between a malignant and a benign adrenal tumor and subsequently select candidates for adrenal surgery.

METHODS

Beginning in July 1995, oncologic patients with adrenal incidentaloma underwent abdominal ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), and [ 18 ]fluoro-2-deoxy-D-glucose positron emission tomography (18-FDG-PET). Consecutively in all patients adrenalectomy was performed. Histologic findings were compared with the imaging results.

RESULTS

In 42 patients, 33 to 79 years old (mean age, 58 years), 44 adrenal lesions were detectable. Two patients presented with bilateral adrenal masses. At operation, 43 adrenal resections and 3 biopsies were performed. Histologic examination revealed 31 metastases (71%) and 13 adrenal adenomas (29%). In metastases the sensitivity of ultrasonography, CT, MRI, and 18-FDG-PET was 66%, 81%, 100%, and 100%, respectively. For adrenal adenoma, the sensitivity of ultrasonography, CT, MRI, and 18-FDG-PET was 46%, 39%, 100%, and 54%, respectively.

CONCLUSIONS

In oncologic patients with indeterminate adrenal tumors MRI and 18-FDG-PET provide accurate differentiation between metastases and benign adenomas. Positive results of these 2 imaging modalities are highly suggestive for metastatic disease. In cases of negative MRI and 18-FDG-PET results the adrenal lesion corresponds to a benign adenoma that needs no surgical intervention.

Adrenal tumors: how to establish malignancy ?

Discerning malignancy in adrenal tumors largely influences disease management and is, therefore, of utmost importance to both patient and physician. Clinical presentation (e.g. virilization) and baseline hormonal evaluation (e.g. high serum DHEAS) are occasionally of great value but usually provide only limited help in predicting malignancy. The probability of malignancy is clearly related to tumor size, as almost all lesions <3 cm are benign whereas a diameter of >6 cm indicates a high risk of malignancy. Computed tomography (CT) and magnetic resonance imaging (MRI) both contribute significantly to the characterization of adrenal masses. If the attenuation of a homogeneous mass with smooth border is 10 Hounsfield units or less in unenhanced CT the diagnosis of a lipid rich adenoma is established. Similarly, enhancement washout of more than 50% in CT at 10-15 min suggests a benign lesion. In MRI both rapid contrast enhancement after gadolinium followed by rapid washout and signal intensity loss using opposed-phase image in chemical shift analysis also indicate the presence of an adenoma. In contrast, adrenal carcinomas--but also pheochromocytomas--typically present as inhomogeneous lesion with intermediate-to-high intensity on T2 images in MRI. Margins and enhancement after contrast media in CT are irregular in adrenal carcinoma. Other imaging techniques either offer little additional information (NP-59 scintigraphy) or have not yet been fully established (positron emission tomography). Fine needle aspiration/cut biopsy is at present restricted to patients with a known extra-adrenal malignancy and suspected adrenal metastasis as the only evidence of disseminated disease. Adrenal tumors classified as benign undergo follow-up imaging to assess tumor growth. If an increase in diameter of >1 cm is seen, surgical removal is recommended. Even after tumor removal the diagnosis of dignity may remain difficult. Diagnostic scores together with new immunohistological markers are the methods of choice to assess malignancy. In conclusion, an interdisciplinary approach with a structured use of available diagnostic tools is needed to classify adrenal tumors correctly.

The clinically inapparent adrenal mass: update in diagnosis and management

Clinically inapparent adrenal masses are incidentally detected after imaging studies conducted for reasons other than the evaluation of the adrenal glands. They have frequently been referred to as adrenal incidentalomas. In preparation for a National Institutes of Health State-of-the-Science Conference on this topic, extensive literature research, including Medline, BIOSIS, and Embase between 1966 and July 2002, as well as references of published metaanalyses and selected review articles identified more than 5400 citations. Based on 699 articles that were retrieved for further examination, we provide a comprehensive update of the diagnostic and therapeutic approaches focusing on endocrine and radiological features as well as surgical options. In addition, we present recent developments in the discovery of tumor markers, endocrine testing for subclinical disease including autonomous glucocorticoid hypersecretion and silent pheochromocytoma, novel imaging techniques, and minimally invasive surgery. Based on the statements of the conference, the available literature, and ongoing studies, our aim is to provide practical recommendations for the management of this common entity and to highlight areas for future studies and research.