Computed tomography of adrenocortical carcinoma containing macroscopic fat

Imaging incidental adrenal lesions

Incidental adrenal masses are among the most common incidental lesions detected on cross-sectional imaging. The majority are benign lesions, adenomas and myelolipomas being the most common. Simple cross-sectional imaging techniques using CT and MRI permit the characterization of over 80%, thereby requiring no further imaging. The remaining lesions are considered indeterminate. These lesions consist of benign and malignant lesions sharing imaging features. Further imaging and management of these indeterminate lesions should be guided by close collaboration between different specialists in an MDT setting. Advanced imaging options include dedicated adrenal scintigraphy, positron emission tomography CT, biopsy and surveillance. Biochemical and hormonal evaluation is also important to identify hyperfunctioning adrenal lesions. This review focuses on imaging features of benign and malignant adrenal masses used for characterization and suggests an imaging pathway for indeterminate adrenal masses.

Management of incidental adrenal nodules: a survey of abdominal radiologists conducted by the Society of Abdominal Radiology Disease-Focused Panel on Adrenal Neoplasms

Adrenal incidentalomas are common findings discovered at abdominal CT and MRI, yet the most appropriate management remains controversial and guidelines vary. The Society of Abdominal Radiology (SAR) Disease-Focused Panel on Adrenal Neoplasms sought to determine the practice patterns of abdominal radiologists regarding the interpretation and management of adrenal incidentalomas. An electronic survey consisting of eleven multiple choice questions about adrenal incidentalomas was developed and distributed to the email list of current and past SAR members. The response rate was 11.8% (423/3581) and most respondents were academic radiologists (80.6%). The 2017 American College of Radiology White Paper was the most used guideline, yet the management of indeterminate adrenal incidentalomas was highly variable with no single management option reaching a majority. Hormonal evaluation and endocrinology consultation was most often rarely or never recommended. The results of the survey indicate wide variability in the interpretation of imaging findings and management recommendations for incidental adrenal nodules among surveyed radiologists. Further standardization of adrenal incidentaloma guidelines and education of radiologists is needed.

Adrenal Myelolipoma Masquerading as an Adrenal Malignancy

An adrenal myelolipoma presenting with suspicious features may pose a diagnostic challenge to surgeons and endocrinologists. In this case report of an adult patient with undiagnosed congenital adrenal hyperplasia presenting with bilateral adrenal masses, we review his radiographic and clinical findings which were highly suspicious for adrenal malignancy. Features of adrenal myelolipoma that may resemble malignant lesions are reviewed. This case report highlights important features of adrenal myelolipoma that the surgeon and endocrinologist should be aware of. The importance of avoiding overtreating adrenal myelolipomas presenting as tumors of uncertain malignant potential is crucial.

Technical and Interpretive Pitfalls in Adrenal Imaging

The adrenal gland may exhibit a wide variety of pathologic conditions. A number of imaging techniques can be used to characterize these, although it is not always possible to attain a definitive diagnosis radiologically. Incorrect diagnoses may be made if radiologists are not attentive to technical parameters and interpretive factors associated with adrenal gland imaging. Hence, an appreciation of the intricacies of adrenal imaging strategies and characterization is required; this can be aided by understanding the pitfalls of adrenal imaging. Technical pitfalls at CT may relate to the imaging parameters, including region of interest characteristics, tube voltage selection, and the timing of contrast material-enhanced imaging. With MRI, imaging acquisition technique and evaluation of the reference tissues used in chemical shift MRI are important considerations that can directly influence image interpretation. Interpretive errors may occur when evaluating adrenal washout at CT without considering other radiologic features, including the size of adrenal nodules, the presence of fat or calcification, the attenuation of nodules, and atypical imaging features. The characterization of an incidental adrenal lesion as benign or malignant does not end the role of the radiologist; consideration as to whether an adrenal lesion is associated with endocrine dysfunction is required. While imaging may not be optimal for establishing endocrine activity, there are imaging features from which radiologists may infer function. In cases of known endocrine activity, imaging can guide clinical management, including further investigations such as venous sampling. ^©RSNA, 2020.

Imaging of Adrenal-Related Endocrine Disorders

Endocrine disorders associated with adrenal pathologies can be caused by insufficient adrenal gland function or excess hormone secretion. Excess hormone secretion may result from adrenal hyperplasia or hormone-secreting (ie, functioning) adrenal masses. Based on the hormone type, functioning adrenal masses can be classified as cortisol-producing tumors, aldosterone producing tumors, and androgen-producing tumors, which originate in the adrenal cortex, as well as catecholamine-producing pheochromocytomas, which originate in the medulla. Nonfunctioning lesions can cause adrenal gland enlargement without causing hormonal imbalance. Evaluation of adrenal-related endocrine disorders requires clinical and biochemical workup associated with imaging evaluation to reach a diagnosis and guide management.

Adrenal cortical carcinoma: pathology, genomics, prognosis, imaging features, and mimics with impact on management

Adrenocortical carcinoma (ACC) is a rare tumor with a poor prognosis. Most tumors are either metastatic or locally invasive at the time of diagnosis. Differentiation between ACC and other adrenal masses depends on clinical, biochemical, and imaging factors. This review will discuss the genetics, pathological, and imaging feature of ACC.

Mimics, pitfalls, and misdiagnoses of adrenal masses on CT and MRI

Due to the widespread use of imaging, incidental adrenal masses are commonly encountered. A number of pitfalls can result in misdiagnosis of these lesions, including inappropriate choice of imaging technique, presence of pseudolesions, and overlap of imaging features of different adrenal lesions. This article explores the potential pitfalls in imaging of the adrenal glands, on computed tomography and magnetic resonance imaging, that can lead to misinterpretation. Clues to correct diagnoses are provided to evade potential misinterpretation.

Adrenal collision tumour comprised of adrenocortical carcinoma and myelolipoma in a patient with congenital adrenal hyperplasia

Adrenal myelolipoma is a benign tumour characterized by the presence of macroscopic fat. Further workup is not necessary if a diagnosis of adrenal myelolipoma is obtained via imaging. We report the first case of adrenal collision tumour comprised of adrenocortical carcinoma and myelolipoma in a patient with bilateral myelolipomas and congenital adrenal hyperplasia. Computed tomography showed a large right adrenal mass consisting of two different components: soft tissue with peripheral heterogeneous enhancement and macroscopic fat. Imaging findings reflected features of both adrenocortical carcinoma and myelolipoma. Although this entity is rare, collision tumour containing an adrenocortical carcinoma component should be suspected if portions of an adrenal mass partially consist of peripheral heterogeneous enhancement.

Renal and adrenal masses containing fat at MRI: Proposed nomenclature by the society of abdominal radiology disease-focused panel on renal cell carcinoma

This article proposes a consensus nomenclature for fat-containing renal and adrenal masses at MRI to reduce variability, improve understanding, and enhance communication when describing imaging findings. The MRI appearance of "macroscopic fat" occurs due to a sufficient number of aggregated adipocytes and results in one or more of: 1) intratumoral signal intensity (SI) loss using fat-suppression techniques, or 2) chemical shift artifact of the second kind causing linear or curvilinear India-ink (etching) artifact within or at the periphery of a mass at macroscopic fat-water interfaces. "Macroscopic fat" is most commonly observed in adrenal myelolipoma and renal angiomyolipoma (AML) and only rarely encountered in other adrenal cortical tumors and renal cell carcinomas (RCC). Nonlinear noncurvilinear signal intensity loss on opposed-phase (OP) compared with in-phase (IP) chemical shift MRI (CSI) may be referred to as "microscopic fat" and is due to: a) an insufficient amount of adipocytes, or b) the presence of fat within tumor cells. Determining whether the signal intensity loss observed on CSI is due to insufficient adipocytes or fat within tumor cells cannot be accomplished using CSI alone; however, it can be inferred when other imaging features strongly suggest a particular diagnosis. Fat-poor AML are homogeneously hypointense on T₂ -weighted (T₂ W) imaging and avidly enhancing; signal intensity loss at OP CSI is uncommon, but when present is usually focal and is caused by an insufficient number of adipocytes within adjacent voxels. Conversely, clear-cell RCC are heterogeneously hyperintense on T₂ W imaging and avidly enhancing, with the signal intensity loss observed on OP CSI being typically diffuse and due to fat within tumor cells. Adrenal adenomas, adrenal cortical carcinoma, and adrenal metastases from fat-containing primary malignancies also show signal intensity loss on OP CSI due to fat within tumor cells and not from intratumoral adipocytes. Level of Evidence: 5 Technical Efficacy Stage: 3 J. Magn. Reson. Imaging 2019;49:917-926.

Delayed presentation of a virilising, pure testosterone-secreting adrenocortical carcinoma with coexistent composite myelolipoma and a venous thrombus extending to the heart

A 40-year-old normotensive woman presented with abnormal facial hair for 4 years and amenorrhoea for 13 years. Hormonal, biochemical and haematological evaluation showed isolated elevation of serum testosterone and free testosterone. Her follicle-stimulating hormone and luteinising hormone were in the premenopausal range. Until recently she had reconciled to early 'menopause' and visited beauty clinics but never sought medical evaluation. Imaging revealed an enhancing left adrenal mass with fat densities and venous thrombus extending through the inferior vena cava to a 7 cm mass in the right atrium. She underwent left kidney-preserving surgery utilising hypothermic cardiopulmonary bypass with early clamping of the pulmonary artery without circulatory arrest. Histology showed adrenocortical carcinoma with composite incidental myelolipoma and neoplastic thrombus. At 2 months, testosterone has normalised and she is doing well. Isolated testosterone-secreting adrenocortical carcinoma with massive venous thrombus is rare as is coincidental composite macroscopic myelolipoma.

Lipomatous tumours in adrenal gland: WHO updates and clinical implications

Adrenal lipomatous tumour is a group of adrenal tumours with a significant component of adipose tissue. According to the current World Health Organization (WHO) classification of tumours of endocrine organs, adrenal myelolipoma is the only entity amongst the group of tumours being described. In the literature, other more recently documented adrenal lipomatous tumours included 24 lipomas, 32 teratomas and 16 angiomyolipomas. Rare fatty tumours of the adrenal gland comprised liposarcoma, hibernoma, adrenocortical tumours with fat component and rare adrenal tumours with fat component. Myelolipoma comprises approximately 3% of primary adrenal tumour. It is noted more commonly in females and in the right adrenal gland. Approximately 40 bilateral myelolipomas were reported. The tumour is most frequently recorded in patients between fifth and seventh decades of life. Adrenal lipomas are often seen in males and in the right adrenal gland. They were commonly noted in patients in the sixth decade of life. The diagnosis could only be possible on examination of the surgically removed specimen. Adrenal teratomas were more common in females and with a bimodal age distribution. Slightly over 60% of the patients with adrenal teratoma are symptomatic. Adrenal angiomyolipomas were often symptomatic, more common in females and in the fifth decades of life. To conclude, adrenal lipomatous tumour is uncommon. They are often benign and non-functional. It is important to recognize the features of this group of lipomatous tumours in the adrenal gland as they are being detected on increasing incidence as a result of the wide-spread use of modern imaging modalities.

Update on CT and MRI of Adrenal Nodules

OBJECTIVE

The objective of this article is to review the current role of CT and MRI for the characterization of adrenal nodules.

CONCLUSION

Unenhanced CT and chemical-shift MRI have high specificity for lipid-rich adenomas. Dual-energy CT provides comparable to slightly lower sensitivity for the diagnosis of lipid-rich adenomas but may improve characterization of lipid-poor adenomas. Nonadenomas containing intracellular lipid pose an imaging challenge; however, nonadenomas that contain lipid may be potentially diagnosed using other imaging features. Multiphase adrenal washout CT can be used to differentiate lipid-poor adenomas from metastases but is limited for the diagnosis of hypervascular malignancies and pheochromocytoma.

Value of 18-F-FDG PET/CT and CT in the Diagnosis of Indeterminate Adrenal Masses

The purpose of this paper was to study the value of 18-FDG PET/CT and reassess the value of CT for the characterization of indeterminate adrenal masses. 66 patients with 67 indeterminate adrenal masses were included in our study. CT/MRI images and 18F-FDG PET/CT data were evaluated blindly for tumor morphology, enhancement features, apparent diffusion coefficient values, maximum standardized uptake values, and adrenal-to-liver maxSUV ratio. The study population comprised pathologically confirmed 16 adenomas, 19 metastases, and 32 adrenocortical carcinomas. Macroscopic fat was observed in 62.5% of the atypical adenomas at CT but not in malignant masses. On 18F-FDG PET/CT, SUVmax and adrenal-to-liver maxSUV ratio were significantly lower in adenomas than in malignant tumors. An SUVmax value of less than 3.7 or an adrenal-to-liver maxSUV ratio of less than 1.29 is highly predictive of benignity.

Incidental Adrenal Nodules and Masses: The Imaging Approach

Adrenal nodules are detected with increasing frequency. The National Institute of Health (NIH), American College of Radiology (ACR), and the American Association of Clinical Endocrinologists and American Association of Endocrine Surgeons (AACE/AAES) have produced guidelines for the management of incidental adrenal nodules. This review provides a summary of the consensus radiologic approach to these nodules.

Adrenal imaging (Part 1): Imaging techniques and primary cortical lesions

Adrenal glands can be affected by a variety of lesions. Adrenal lesions can either be primary, of adrenal origin, or secondary to other pathologies. Primary adrenal lesions can further be either of cortical or medullary origin. Functioning adrenal lesions can also give clues to the histologic diagnosis and direct workup. Over the years, various imaging techniques have been developed that have increased diagnostic accuracy and helped in better characterization of adrenal lesions non-invasively. In the first part of the two part series, we review adrenal imaging techniques and adrenal cortical tumors such as adenomas, adrenocortical tumors, adrenal hyperplasia and oncocytomas.

“Dominant” Myelolipoma Encasing Adrenal Cortical Carcinoma

Although myelolipomas of the adrenal glands are detected with increasing frequency with advances in imaging, the occurrence of myelolipoma with adrenal cortical carcinoma remains very rare. We present a case of combined myelolipoma with adrenal cortical carcinoma in a 47-year-old man. In previously reported cases of adrenal cortical carcinoma and myelolipoma, the latter occurred as incidental foci within or peripheral to the carcinoma, perhaps representing “myelolipomatous metaplasia” rather than true neoplasia. We describe a new finding, in which the myelolipomatous component consisted of a large mass adjacent and dominant to the carcinoma. The presence of these 2 defined and apparently independent tumors suggests, in this case, the occurrence of collision or synchronous neoplastic events, rather than of metaplasia.

Surgical management of adrenocortical tumours

The surgical treatment of adrenal tumours has evolved over the past century, as has our understanding of which hormones are secreted by the adrenal glands and what these hormones do. This article reviews the preoperative evaluation of patients with adrenal tumours that could be benign or malignant, including metastases. The biochemical evaluation of excess levels of hormones is discussed, as are imaging characteristics that differentiate benign tumours from malignant tumours. The options for surgical management are outlined, including the advantages and disadvantages of various open and laparoscopic approaches. The surgical management of adrenocortical carcinoma is specifically reviewed, including controversies in operative approaches as well as surgical management of invasive or recurrent disease.

Adrenocortical carcinoma

Adrenocortical carcinoma (ACC) is a rare endocrine malignancy, often with an unfavorable prognosis. Here we summarize the knowledge about diagnosis, epidemiology, pathophysiology, and therapy of ACC. Over recent years, multidisciplinary clinics have formed and the first international treatment trials have been conducted. This review focuses on evidence gained from recent basic science and clinical research and provides perspectives from the experience of a large multidisciplinary clinic dedicated to the care of patients with ACC.