Incidentally discovered adrenal masses: evaluation with gadolinium enhancement and fat-suppressed MR imaging at 0.5 T

Biochemically Silent Pheochromocytoma in an Asymptomatic Patient With a Unilateral Lipid-Poor Adrenal Adenoma

In this case, a Caucasian woman was incidentally found to have a left adrenal gland incidentaloma a decade ago. Initial tests indicated a non-functional lipid-poor adenoma, but ongoing surveillance revealed irregularities in biochemical testing for pheochromocytoma. The patient was concurrently taking an SNRI, known to elevate biochemical markers artificially. Given the adenoma's growth and mild biochemical abnormalities, laparoscopic surgery was performed, and the tumor was found to be a 2.4 cm × 1.8 cm pheochromocytoma. Following the procedure, hormone levels normalized, and the patient experienced relief from symptoms. This case underscores the rarity of pheochromocytomas, emphasizing the importance of accurate diagnosis and effective management. Imaging techniques, notably computed tomography (CT) and magnetic resonance imaging (MRI), played a crucial role in localization, particularly through contrast-enhanced methods. Key characteristics like Hounsfield density, enhancement patterns, and washout behavior aided in distinguishing diverse adrenal masses. For cases where imaging had limitations, complementary techniques such as 23I-metaiodobenzylguanidine (MIBG) scintigraphy, specialized MR sequences, and GA-DOTATATE scans provided supplementary diagnostic insights, collectively contributing to a comprehensive clinical understanding. Despite advancements, challenges persist in differentiating specific adrenal tumors, highlighting the need for continued research and refined imaging methodologies.

Asymptomatic and Biochemically Silent Pheochromocytoma with Characteristic Findings on Imaging

Pheochromocytomas are tumors that originate from the chromaffin tissue of the adrenal medulla and commonly produce catecholamines. The diagnosis is typically established by the measurement of catecholamines or their metabolites in urine or plasma, and tumors are localized with the use of radiographic and scintigraphic studies. Pheochromocytomas can occur in asymptomatic patients, and the preferred treatment is surgical removal of the tumor. We report a 48-year-old male with a left adrenal incidentaloma, which progressively increased in size from 1.1 cm to 2.6 cm over a 4-year period, as measured by an adrenal computed tomography (CT) scan. Throughout his entire course of treatment, he was asymptomatic with normal blood pressure readings. His biochemical screening was unremarkable for the first three years of tumor surveillance. Follow-up imaging, including CT and MRI, showed findings suspicious for pheochromocytoma, and the diagnosis was ultimately made with the combination of imaging and laboratory studies. He underwent laparoscopic resection of the adrenal mass with confirmation of pheochromocytoma on histology. This case illustrates how CT and MRI findings can alert providers to the presence of a pheochromocytoma, even in an asymptomatic, biochemically negative patient.

Adrenal Hemangioma Definite Diagnosis on CT, MRI, and FDG PET in a Patient With Primary Lung Cancer

Distinguishing adrenal incidentalomas (5% of all abdominal CT scans) from metastasis is a frequent diagnostic challenge in primary malignancies with a propensity for adrenal spread, such as lung cancer. Adrenal myelolipoma and adenoma can be definitively characterized as benign by demonstrating gross and microscopic fat, respectively, on CT and MRI and an absence of abnormal uptake on PET. Unfortunately, adrenal sampling is frequently necessary in indeterminate cases for adequate staging of extra-adrenal primary malignancy. We present a lung cancer case in which definite characterization of a rare adrenal hemangioma with CT, PET, and MRI avoided unnecessary adrenal sampling.

MANAGEMENT OF ENDOCRINE DISEASE: Imaging for the diagnosis of malignancy in incidentally discovered adrenal masses: a systematic review and meta-analysis

OBJECTIVE

Adrenal masses are incidentally discovered in 5% of CT scans. In 2013/2014, 81 million CT examinations were undertaken in the USA and 5 million in the UK. However, uncertainty remains around the optimal imaging approach for diagnosing malignancy. We aimed to review the evidence on the accuracy of imaging tests for differentiating malignant from benign adrenal masses.

DESIGN

A systematic review and meta-analysis was conducted.

METHODS

We searched MEDLINE, EMBASE, Cochrane CENTRAL Register of Controlled Trials, Science Citation Index, Conference Proceedings Citation Index, and ZETOC (January 1990 to August 2015). We included studies evaluating the accuracy of CT, MRI, or (18)F-fluoro-deoxyglucose (FDG)-PET compared with an adequate histological or imaging-based follow-up reference standard.

RESULTS

We identified 37 studies suitable for inclusion, after screening 5469 references and 525 full-text articles. Studies evaluated the accuracy of CT (n=16), MRI (n=15), and FDG-PET (n=9) and were generally small and at high or unclear risk of bias. Only 19 studies were eligible for meta-analysis. Limited data suggest that CT density >10HU has high sensitivity for detection of adrenal malignancy in participants with no prior indication for adrenal imaging, that is, masses with ≤10HU are unlikely to be malignant. All other estimates of test performance are based on too small numbers.

CONCLUSIONS

Despite their widespread use in routine assessment, there is insufficient evidence for the diagnostic value of individual imaging tests in distinguishing benign from malignant adrenal masses. Future research is urgently needed and should include prospective test validation studies for imaging and novel diagnostic approaches alongside detailed health economics analysis.

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.

Pheochromocytoma with inferior vena cava thrombosis: An unusual association

Pheochromocytomas have been described in association with vascular abnormalities like renal artery stenosis. A 48-year-old man was admitted to our hospital with the complaints of headache, sweating, anxiety, dizziness, nausea, vomiting and hypertension. For last several days, he was having a dull aching abdominal pain. Abdominal computed tomography (CT) revealed the presence of a left adrenal pheochromocytoma. An inferior vena cava (IVC) venogram via the right jugular vein demonstrated occlusion of the IVC inferior to the right atrium. Surgical removal of pheochromocytoma was done, followed by anticoagulant treatment for IVC thrombosis, initially with subcutaneous low molecular weight heparin, and then with oral warfarin, resulting in restoration of patency. To the best of our knowledge, the occurrence of pheochromocytoma in IVC thrombosis has not been reported so far from India. Possible mechanisms of such an involvement are discussed.

Dynamic contrast enhanced MRI in the differential diagnosis of adrenal adenomas and malignant adrenal masses

OBJECTIVE

To evaluate the value of dynamic MR imaging in the differential diagnosis of adrenal adenomas and malignant tumors, especially in cases with atypical adenomas.

MATERIALS AND METHODS

Sixty-four masses (48 adenomas, 16 malignant tumors) were included in this prospective study. Signal loss of masses was evaluated using chemical shift MR imaging. Five dynamic series of T1-weighted spoiled gradient echo (FFE) images were obtained, with the acquisition starting simultaneously with i.v. contrast administration (0-100 s) followed by a T1-weighted FFE sequence in the late phase (5th minute). Contrast enhancement patterns in the early (25th second) and late (5th minute) phase images were evaluated. For the quantitative evaluation, signal intensity (SI)-time curves were obtained according to the SIs on the 0th, 25th, 50th 75th and 100th second. Also, the wash-in rate, maximum relative enhancement, time-to-peak, and wash-out of contrast at 100 s of masses in both groups were calculated. The statistical significance was determined by Mann-Whitney U test. To evaluate the diagnostic performance of the quantitative tests, receiver operating characteristic (ROC) analysis was performed.

RESULTS

Chemical shift MR imaging was able to differentiate 44 out of 48 adenomas (91.7%) from non-adenomas. The 4 adenomas (8.3%) which could not be differentiated from non-adenomas by this technique did not exhibit signal loss on out-of-phase images. With a cut-off value of 30, SI indices of adenomas had a sensitivity of 93.8%, specificity of 100% and a positive predictive value of 100%. On visual evaluation of dynamic MR imaging, early phase contrast enhancement patterns were homogeneous in 75% and punctate in 20,83% of the adenomas; while patchy in 56.25% and peripheral in 25% of the malignant tumors. On the late phase images 58.33% of the adenomas showed peripheral ring-shaped enhancement and 10.41% showed heterogeneous enhancement. All of the malignant masses showed heterogeneous enhancement. At the 25th second, the SIs and wash-in rates of the adenomas were significantly higher than those of the malignant masses (p=0.010). Time-to-peak enhancement of the malignant masses was significantly longer than that of the adenomas. With a cut-off value of 52.85 s, the time-to-peak enhancement had 87.5% sensitivity and 80% specificity.

CONCLUSION

Chemical shift MR has a high sensitivity and specificity in the differential diagnosis of adenomas and malignant adrenal masses. However, taking into consideration only the atypical adenomas, chemical shift MRI is of no diagnostic value. Although the diagnostic value of dynamic MRI is lower than chemical shift MRI, in the atypical cases contrast enhancement patterns and time-to-peak and wash-in rates derived from SI-time curve of dynamic MRI give are contributory to the results of chemical shift MRI.

Mandibular metastasis presenting as the initial maifestation of malignant pheochromocytoma

A case of 59-year-old male patient presenting with metastasis to the mandible from malignant pheochromocytoma is described. The conventional radiographs and CT images suggested that the lesion was malignant osteogenic tumors or metastatic tumors due to the existence of calcification and widespread periosteal sunburst spiculation. On MRI, an expansive mass was clearly depicted and the signal intensities of the lesion were low to intermediate on T1 weighted image with intermediate to high signal intensity on T2 weighted image. A strong enhancement of the lesion was also observed on contrast enhanced T1 weighted image. On maximum intensity projection image in the arterial phase, the mass showed exceedingly early enhancement and excessively dislocated adjacent vessels. The diagnosis of a pheochromcytoma was difficult on the basis of these imagings. The final diagnosis was based on a biopsy of the mandible and I-131 Meta-iodobenzylguanidine scintigraphy (MIBG) scintigraphy. A primary lesion of the right adrenal showed low uptake due to wide centric necrosis and metastatic lesions of liver, lumber vertebrae, ribs and sacroiliac joint showed high uptake on the I-131 MIBG scintigraphy. The final diagnosis was nonfunctioning malignant pheochromocytoma due to the absence of elevation of catecholamine or its metabolite.

Three-point Dixon chemical-shift imaging for evaluating articular cartilage defects in the knee joint on a low-field-strength open magnet

OBJECTIVE

The purpose of our study was to assess the value of a modified three-point Dixon MR technique for evaluating articular cartilage defects in the knee joint on a low-field-strength open magnet, correlated with arthroscopy.

SUBJECTS AND METHODS

Twenty consecutive patients who underwent both MR imaging and arthroscopy of the knee joint for suspected internal derangement were examined. A modified three-point Dixon MR sequence with a single radiofrequency echo single-scan method for water and fat separation with correction of the static field inhomogeneities was performed on a 0.35-T open magnet to obtain fat suppression. The MR images were prospectively evaluated for the presence and grade of articular cartilage defects.

RESULTS

Uniform fat suppression was obtained in all patients using the modified three-point Dixon technique. Fifty-nine cartilage abnormalities were identified in 19 patients on the basis of arthroscopy. Forty-seven of 59 arthroscopically proven abnormalities were prospectively detected on MR imaging. Compared with arthroscopy, the overall sensitivity of the modified three-point Dixon technique in detecting cartilage lesions was 80% and the specificity was 73%. Sixty-five percent of the cartilage abnormalities were graded identically on MR imaging and arthroscopy.

CONCLUSION

The modified three-point Dixon sequence is a useful technique for achieving fat suppression in the knee joint on a 0.35-T open magnet. It is a sensitive and specific technique for the assessment of cartilage abnormalities in the knee.

Magnetic resonance imaging of the thorax. Past, present, and future

Magnetic resonance imaging is a valuable modality of extreme flexibility for specific problem-solving capability in the thorax. This article reviews MR applications in the imaging of great vessels, which are currently the most important applications in the thorax; other established applications in the thorax; and pulmonary functional MR imaging.

Diagnosis and treatment of adrenal incidentaloma. A cost-effectiveness analysis

Methods of meta-analysis, decision analysis, and cost-effectiveness analysis were applied to the adrenal incidentaloma dilemma. It was shown that the life expectancy of patients with adrenal incidentalomas is decreased by a mean of about 1 year if left undiagnosed and untreated--more in cases of larger incidentalomas. Overall, selective analysis of adrenomedullary hormonal function (by urinary metanephrines) is the most cost-effective strategy. Other strategies, such as more extensive hormonal testing, imaging, and fine needle aspiration cytology may provide better cost-effectiveness in subgroups of patients, identified by signs, symptoms, and incidentaloma morphology. Full adrenal hormonal analysis is indicated in patients with larger (> or = 6 cm) incidentalomas and if the combination of hypertension and hypokalemia suggests Conn's disease. Small or medium-sized adrenal incidentalomas may be ignored if MR imaging or other tests suggest benign pheochromocytoma disorder, or patients are elderly, or both.

Magnetic resonance imaging of the thorax. Past, present, and future

Magnetic resonance is a valuable modality of extreme flexibility for specific problem-solving capability in the thorax. This article reviews MR applications in the imaging of great vessels, which are currently the most important applications in the thorax; other established applications in the thorax; and pulmonary functional MR imaging.