Allelic Variant of Armadillo Repeat Containing Protein 5 (ARMC5) in Myelolipoma Mimicking Pheochromocytoma: A Case Report

Adrenal myelolipomas are benign adrenocortical tumors composed of adipose tissue mixed with hematopoietic precursor cells. An association of myelolipoma with adrenal cortical adenoma is rare and the pathogenesis of these tumors remains unclear. Here we present a case of an incidentally discovered adrenal tumor with radiologic characteristics of a myelolipoma who underwent adrenalectomy due to biochemical suspicion for pheochromocytoma. The final pathology, however, revealed a myelolipoma with a co-existing adrenal cortical adenoma without evidence of pheochromocytoma. Genetic analysis revealed the presence of a hitherto unreported heterozygous variant, c.329C>A (p.Ala110Asp), of the armadillo repeat-containing protein 5 (ARMC5) gene which when inactivated is commonly associated with bilateral adrenal nodularity.

Adrenal nodules for the non-specialist: What to look out for and when to refer

Almost all medical specialities utilise cross-sectional imaging of the abdomen to evaluate many different medical conditions. This ever-increasing use of cross-sectional imaging has led to a dramatic increase in the detection rate of adrenal nodules. Following appropriate biochemical and radiological evaluation, the vast majority of these are shown to be benign adrenal adenomas. A small minority are diagnosed with a functional or malignant lesion that may result in significant morbidity and mortality requiring specialist management.

Hyperaldosteronism from a large adrenal adenoma in a patient with bilateral adrenal nodules

Primary aldosteronism (PA) is a potentially reversible cause of uncontrolled hypertension. Early diagnosis and timely management of PA can prevent end-organ damage. Aldosteronoma Resolution Score (ARS) is a useful tool to predict cure rates and resolution of hypertension after adrenalectomy.

Incidentally Detected Bilateral Adrenal Nodules in Patients Without Cancer: Is Further Workup Necessary?

OBJECTIVE

The purpose of this study was to determine the rate of malignancy in incidentally detected bilateral adrenal masses in patients with no known history of cancer.

MATERIALS AND METHODS

A retrospective search of CT reports of patients with incidentally detected bilateral adrenal nodules was performed from January 1, 2002, to January 1, 2014. Patients were excluded if they had a known cancer or suspected functioning adrenal tumor; 161 patients were included. Nodules were characterized as benign or malignant on the basis of imaging features at the index CT examination, imaging features at subsequent adrenal protocol CT or MRI, imaging stability for a minimum of 1 year, or clinical follow-up of a minimum of 2 years.

RESULTS

Mean nodule size was 1.8 cm (range, 0.7-4.9 cm). There were no cases of primary or secondary adrenal malignancy (95% CI, 0.00-0.023). The nodules diagnosed on index CT scans were 73 adrenal adenomas and two myelolipomas. Seventy-four nodules were subsequently characterized as adrenal adenomas on the basis of imaging findings. Of the 113 indeterminate nodules that had imaging follow-up, 111 were stable at the latest follow-up examination. One nodule grew 26% over 8.1 years, and the other grew 59% over 12.4 years. Clinical follow-up of patients with 60 indeterminate nodules revealed no evidence of adrenal malignancy.

CONCLUSION

No case of malignancy was found in 322 incidentally detected bilateral adrenal nodules at CT of patients without known cancer. Imaging follow-up of such lesions may be unnecessary.

Diagnostic performance of unenhanced computed tomography and 18 F-fluorodeoxyglucose positron emission tomography in indeterminate adrenal tumours

OBJECTIVE

Evidence on the diagnostic performance of adrenal imaging is limited. We aimed to assess the diagnostic performance of unenhanced computed tomography (CT) and ¹⁸ F-fluorodeoxyglucose (¹⁸ FDG) positron emission tomography (PET)/CT imaging in a high-risk population for adrenal malignancy using an optimal reference standard.

DESIGN

Retrospective cohort study.

METHODS

Imaging studies of patients with adrenal nodules who underwent adrenal biopsy and/or adrenalectomy between 1994 and 2014 were reviewed and compared to the reference standard of histology. Eighty % of patients presented with known or suspected extra-adrenal malignancy.

RESULTS

Unenhanced abdominal CT was performed in 353 patients with adrenal lesions; median size was 3 (0.7-15) cm and median radiodensity was 33 (-21-78) Hounsfield units (HU). Radiodensity of >10 HU diagnosed malignancy with a sensitivity of 100%, specificity of 33%, positive predictive value (PPV) of 72% and negative predictive value (NPV) of 100%. ¹⁸ FDG-PET/CT was performed in 89 patients; median tumour size was 2.1 (0.7-9.2) cm. Maximum standardized uptake (SUV max) was higher in malignant lesions when compared to benign lesions (median=10 [2.3-29.4] vs 3.7 [1.4-24.5], respectively, P<.0001). Similarly, median SUV max lesion to SUV max liver ratio (ALR) in malignant lesions was higher than in benign lesions (median=3 [0.74-13.4] vs 1.2 [0.5-6.6], respectively, P<.0001). ¹⁸ FDG-PET/CT ALR >1.8 diagnosed malignancy with a sensitivity of 87%, specificity of 84%, PPV of 85% and NPV of 86%.

CONCLUSION

Noncontract CT radiodensity of ≤10 HU excludes malignancy even in a high-risk population. For indeterminate adrenal lesions, given a superior specificity, ¹⁸ FDG-PET/CT could be considered as a second stage imaging study.

Adrenal incidentalomas: are they being worked up appropriately?

INTRODUCTION

Adrenal incidentalomas are defined as masses picked up on imaging studies that were done for apparently different reasons. With frequent use of imaging modalities, incidental adrenal masses are commonly encountered in clinical practice. Guidelines are currently available for the diagnosis and management of adrenal incidentalomas, but the appropriateness of initial work-up and subsequent follow-up of incidental adrenal masses in the community hospital setting is unknown.

OBJECTIVE

We studied the appropriateness of initial work-up and follow-up of incidental adrenal masses discovered on abdominal computerized tomography (CT).

METHODS

In our retrospective study, we reviewed sequential CT scans of the abdomen performed in the month of January 2010 at a community hospital. Once patients with one or more adrenal masses were identified, outpatient charts for initial biochemical testing and follow-up imaging were obtained either through directly accessing the electronic medical records or through contacting primary care physician's offices. Patient charts were reviewed to assess the data for the next 2 years following the discovery of an adrenal abnormality.

RESULTS

Twenty adrenal masses were incidentally discovered on 723 abdominal CTs performed within the month of January 2010 resulting in an overall incidence of 2.76%. Of the patients with incidentally discovered adrenal masses, appropriate biochemical and follow-up imaging were only performed in patients referred to an endocrinologist (2 of 20 patients). Thirty percent of patients with incidental masses received a repeat CT scan for non-adrenal reasons, and no change in the mass size was noted.

CONCLUSION

Despite published guidelines, the initial work-up and follow-up of patients with an incidentally discovered adrenal mass is unsatisfactory. There is a desperate need for education of providers regarding appropriate work-up of incidental adrenal masses.

Clinical Outcomes following Percutaneous Radiofrequency Ablation of Unilateral Aldosterone-Producing Adenoma: Comparison with Adrenalectomy

PURPOSE

To compare adrenal radiofrequency (RF) ablation with adrenalectomy in treating unilateral aldosterone-producing adenoma (APA).

MATERIALS AND METHODS

Between April 2008 and September 2013, 44 patients with adrenal venous sampling-confirmed (lateralization index ≥ 4) unilateral APA underwent adrenal RF ablation (12/44 [27%]) or adrenalectomy (32/44 [73%]). Outcomes of adrenal RF ablation (patient age, 51 y ± 11; 4/12 men) were compared with adrenalectomy (patient age, 50 y ± 11; 19/32 men). Blood pressure (145/94 mm Hg ± 19/13 vs 144/89 mm Hg ± 10/8, P = .92), number of antihypertensives (3.0 ± 1.3 vs 2.7 ± 0.89, P = .38), and serum potassium (3.2 mEq/L ± 0.6 vs 3.5 mEq/L ± 0.6, P = .65) of patients were similar before treatment.

RESULTS

RF ablation and adrenalectomy resulted in normokalemia (RF ablation, 4.2 mEq/L ± 0.1, P = .0004; adrenalectomy, 4.3 mEq/L ± 0.6, P < .0001) and normotension (RF ablation, 129/81 mm Hg ± 11/11, P = .02/P = .001; adrenalectomy, 128/85 mm Hg ± 13/12, P < .0001/P = .07) in all patients. Proportions of RF ablation and adrenalectomy patients cured of hypertension (2/12 [17%] vs 12/32 [38%], P = .28) or requiring fewer antihypertensives (7/12 [58%] vs 13/32 [40%], P = .29) were similar. RF ablation patients had a shorter length of stay (0.6 d ± 0.8 [range, 0-2 d] vs 1.7 d ± 1.4 [range, 0-7 d]; P = .01) and less intraoperative blood loss (1.2 mL ± 3 vs 40 mL ±85; P = .01). Procedural complications occurred in 5/32 (15%) adrenalectomy patients (2 major, 3 minor) and in 0/12 RF ablation patients.

CONCLUSIONS

RF ablation to treat APA can achieve similar clinical outcomes as adrenalectomy and results in shorter hospital stays. Larger, prospective trials are needed to validate these results.