Contemporary imaging of incidentally discovered adrenal masses

A Comparison of Near-Infrared Autofluorescence Findings in Benign Versus Malignant Adrenal Tumors

BACKGROUND

Many adrenal tumors are deemed radiologically indeterminate and surgically removed. Adrenal tissue, like parathyroid glands, exhibits near-infrared autofluorescence (NIRAF) properties. This study was designed to investigate the potential of NIRAF to differentiate benign versus malignant adrenal tumors.

METHODS

Patients undergoing adrenalectomy between October 2021 and May 2023 were prospectively studied. Adrenalectomy specimens were inspected with NIRAF imaging. Specimen autofluorescence (AF) characteristics were recorded. Comparisons were made between different tumor types and a logistic regression model was constructed to differentiate benign versus malignant tumors. A receiver operating characteristic curve was used to identify an optimal AF threshold differentiating benign versus malignant tumors.

RESULTS

A total of 108 adrenal specimens were examined: adrenocortical adenomas/other benign lesions (n = 72), pheochromocytomas (n = 18), adrenocortical neoplasms of uncertain behavior (n = 4), and malignant tumors (n = 14). A significant difference in normalized AF intensity was identified when comparing adrenocortical adenomas (3.08 times background) with pheochromocytomas (1.95, p = 0.001) and malignant tumors (1.11, p < 0.0001). The Area Under the Curve differentiating benign vs malignant tumors was 0.87, with an optimal normalized AF threshold at 1.93.

CONCLUSIONS

Different adrenal pathologies exhibit diverse AF properties. These findings suggest a potential intraoperative utility of NIRAF in predicting benign versus malignant nature for radiologically indeterminate adrenal tumors.

Computed tomography in the differential diagnosis of adrenal tumors

Background. Modern methods of topical diagnostics have high accuracy and can determine the morphological structure of the adrenal tumor with high probability before surgery, but none of them has 100% sensitivity and specificity. Contrast-enhanced computed tomography is most commonly used by clinicians. The criteria for the malignancy of an adrenal tumor determined by this method continue to be discussed.

The aim is to evaluate the effectiveness of contrast-enhanced computed tomography in the preoperative diagnosis of adrenal tumors and to analyze errors.

Materials and methods. Contrast-enhanced computed tomography was performed in 69 patients with adrenal tumors. After morphological examination of the removed tumors, the effectiveness of preoperative diagnostics was evaluated with the determination of sensitivity and specificity of the method. If the pre- and postoperative diagnosis did not match, the causes of errors were analyzed.

Results. The attenuation on unenhanced CT in adenomas ranged from 5 to 36 HU, in adrenocortical cancer — from 26 to 80 HU, in pheochromocytomas — from 25 to 99 HU. The attenuation of adenomas on unenhanced CT was significantly less than with pheochromocytomas (p=0.005) and adrenocortical cancer (p=0.012). In the venous phase, no significant differences were found, and in the delayed phase, the attenuation of adenomas was also significantly less than in malignant tumors (p=0.008, p=0.008). The median of absolute percent contrast washout in adenomas was 85%, in pheochromocytes — 59%, in adrenocortical cancer — 57%. When comparing the diagnosis before and after surgery, its non-coincidence was found in 8 cases (10.39%). Two patients (2.59%) with small tumors (diameter of 15 mm) were diagnosed with adenoma in ­combination with pheochromocytoma and adenoma before surgery. After morphological examination, the diagnosis was changed to adrenocortical cancer in combination with adenoma and «mute» pheochromocytoma.

Conclusion. The sensitivity and specificity of contrast-enhanced CT in the diagnosis of adenomas was 95.61% and 94.82%, pheochromocytomas — 95% and 95.08%, adrenocortical cancer — 92.31 and 98.48%. Diagnostic errors of «mute» pheochromocytoma and adrenocortical cancer occurred with small sizes (15 mm) of adrenal tumors.

Case report: Adrenal myelolipoma resected by laparoscopic surgery

Introduction

Adrenal myelolipomas are benign tumors composed mainly of lipomatous elements with myeloid cells. With the development of medical imaging technology, the detection rate has gradually increased. We report a case of adrenal myelolipoma successfully excised through the laparoscope and reviewed existing literature in recent ten years to summarize the feasibility of the laparoscopic approach for this tumor.

Case presentation

Herein, we described a case of adrenal myelolipoma resected by laparoscope in a 63-year-old male patient. He did not have any other symptoms except the incidental finding of a left adrenal mass. An abdominal CT examination revealed a mixed-density lesion containing some amount of adipose tissue. In conjunction with the patient's willingness, we performed a laparoscopic operation to remove the lump. The definite diagnosis was confirmed as an adrenal myelolipoma according to the pathology. The patient recovered well postoperatively and without signs of recurrence at a 5-month follow-up.

Conclusion

Adrenal myelolipoma is commonly benign, asymptomatic, and hormonal inactivity. A surgical strategy is suggested for high-complication-risk patients. The laparoscopic approach is safe and effective with an obvious advantage over open procedures.

Development of Fluorinated NP-59: A Revival of Cholesterol Use Imaging with PET

Imaging of cholesterol use is possible with the ¹³¹I scintiscanning/SPECT agent NP-59. This agent provided a noninvasive measure of adrenal function and steroid synthesis. However, iodine isotopes resulted in poor resolution, manufacturing challenges, and high radiation dosimetry to patients that have limited their use and clinical impact. A ¹⁸F analog would address these shortcomings while retaining the ability to image cholesterol use. The goal of this study was to prepare and evaluate a ¹⁸F analog of NP-59 to serve as a PET imaging agent for functional imaging of the adrenal glands based on cholesterol use. Previous attempts to prepare such an analog of NP-59 have proven elusive. Preclinical and clinical evaluation could be performed once the new fluorine analog of NP-59 production was established. Methods: The recent development of a new reagent for fluorination along with an improved route to the NP-59 precursor allowed for the preparation of a fluorine analog of NP-59, FNP-59. The radiochemistry for the ¹⁸F-radiolabeled ¹⁸F-FNP-59 is described, and rodent radiation dosimetry studies and in vivo imaging in New Zealand rabbits was performed. After in vivo toxicity studies, an investigational new drug approval was obtained, and the first-in-humans images with dosimetry using the agent were acquired. Results: In vivo toxicity studies demonstrated that FNP-59 is safe for use at the intended dose. Biodistribution studies with ¹⁸F-FNP-59 demonstrated a pharmacokinetic profile similar to that of NP-59 but with decreased radiation exposure. In vivo animal images demonstrated expected uptake in tissues that use cholesterol: gallbladder, liver, and adrenal glands. In this first-in-humans study, subjects had no adverse events and images demonstrated accumulation in target tissues (liver and adrenal glands). Manipulation of uptake was also demonstrated with patients who received cosyntropin, resulting in improved uptake. Conclusion: ¹⁸F-FNP-59 provided higher resolution images, with lower radiation dose to the subjects. It has the potential to provide a noninvasive test for patients with adrenocortical diseases.

Detection of incidental adrenal nodules on computed tomography by radiographers

INTRODUCTION

This research investigated whether radiographers' age, qualifications, shift rotations and years of post-qualification experience as a radiographer affect the detection rate of incidental adrenal nodules, also known as adrenal incidentalomas in Malta. Additionally, local statistics of adrenal incidentaloma findings were evaluated.

METHODS

This research consisted of two phases and employed a non-experimental, cross-sectional quantitative approach. Phase 1 comprised of a self-designed data collection sheet to retrospectively determine the occurrence of recalled computed tomography (CT) examinations resulting from an adrenal incidentaloma finding during a six-month period between July 2020 and December 2020. In phase 2, a self-designed questionnaire with anonymised CT scan images (n = 30) displayed on ViewDex (Viewer for Digital Evaluation of X-ray images) was prospectively completed by CT radiographers (n = 23) to identify adrenal incidentalomas on the images.

RESULTS

In phase 1, adrenal incidentalomas were present in 1.4% of contrast-enhanced CT (CECT) examinations (n = 12139), out of which, 79.8% were not acknowledged by the radiographers on the initial scans and patients had to be recalled for a dedicated adrenal CT scan. In phase 2, a statistically significant (p < 0.05) relationship was determined between the radiographers' qualifications, shift rotations and years of post-qualification experience as a radiographer, with their detection rate of adrenal incidentalomas.

CONCLUSION

Findings suggest that radiographers' qualifications, shift rotations and years of post-qualification experience were found to be statistically significant factors affecting their detection rate of adrenal incidentalomas. These could have contributed to one of the reasons for recalling patients, which in turn results in an added burden to both the patient and the Radiology Department.

IMPLICATIONS FOR PRACTICE

Detection of adrenal incidentalomas by radiographers has a direct impact on clinical practice. If identified during the initial CT examination and a further delay scan is performed, this will benefit patients by reducing the risks of additional radiation and potential risks from contrast media administration; prompt diagnosis and treatment. While the Radiology Department benefits in terms of cost effectiveness, work load and appointment scheduling.

Adrenal hemorrhage and hemorrhagic masses; diagnostic workup and imaging findings

Adrenal hemorrhage (AH) is a rare condition. It can be traumatic or non-traumatic. Most common causes are septicemia, coagulopathy or bleeding diathesis, and underlying neoplasms. Other reported less common causes of AH are COVID-19 and neonatal stress. Clinical diagnosis of AH is challenging due to its non-specific presentation and occurrence in the setting of acute medical illness. Therefore, most cases are diagnosed incidentally on imaging. Having high clinical suspicion in the proper clinical setting for AH is crucial to avoid life-threatening adrenal insufficiency that occurs in 16-50% of patients with bilateral AH. We discuss the clinical situations that predispose to AH, review the imaging features on different imaging modalities, highlight a variety of clinical cases, imaging features that should be concerning for an underlying neoplasm, and outline the potential role of interventional radiology in management of AH.

Myelolipoma mimicking osteosarcoma in the distal femur

Introduction and importance

Periosteal reactions indicate malignant bone tumors, including osteosarcoma; establishing an accurate diagnosis is key to determining the most appropriate treatment strategy. We describe a rare case of myelolipoma in the distal femur metaphysis with massive extraskeletal lesions and periosteal reactions.

Case presentation

A 25-year-old woman was referred to our hospital to treat a gradually expanding mass around her knee that grew to the size of a baby's head. She had a history of hydrocephalus caused by congenital cytomegalovirus infection and was bedridden for life. Radiography showed a prominent osteoblastic rim and osteolytic lesion with a moth-eaten appearance. Osteosarcoma was suspected due to excessive extraskeletal invasion and periosteal reactions. T1- and T2-weighted magnetic resonance images showed a high-signal-intensity homologous lesion. Biopsy specimens contained adipose and hematopoietic tissues. A myelolipoma was diagnosed. Due to her fragility, surgical intervention was suspended. Two years after diagnosis, the tumor size did not change.

Clinical discussion

Myelolipomas are benign tumors that typically arise from the adrenal gland and rarely develop in the extremities. This type of tumor typically does not cause any tumor-related symptoms or endocrine disturbances and has been reported as a type of incidentaloma. To effectively manage myelolipoma patients, differential diagnosis of tumors mimicking malignant bone tumors is important.

Conclusion

We successfully managed a destructive ectopic myelolipoma in the distal femoral metaphysis, with massive extraskeletal lesions and periosteal reactions. Clinicians should appropriately differentiate myelolipoma from tumors mimicking malignant bone tumors.

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Report discusses a rare case of ectopic extra-adrenal myelolipoma in the femur.

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The extraskeletal invasion and periosteal reactions resemble malignant bone tumors.

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Clinicians should properly differentiate it from mimics of malignant bone tumors.

Adrenal metastases: early biphasic contrast-enhanced CT findings with emphasis on differentiation from lipid-poor adrenal adenomas

AIM

To evaluate the accuracy of unenhanced attenuation and early biphasic contrast-enhanced computed tomography (CT) in differentiating adrenal metastases (AMs) from lipid-poor adrenal adenomas (AAs).

MATERIALS AND METHODS

This retrospective study included 37 patients with 50 AMs and 86 patients with 89 lipid-poor AAs. Quantitative data including the longest diameter (LD), the shortest diameter (SD), LD/SD ratio, CT attenuation values (CTu, CTa, CTv), degree of enhancement (DEAP, DEPP, DEpeak, APW, RPW), and peak enhanced/unenhanced (PE/U) CT attenuation ratio were obtained. Qualitative data including enhancement pattern, location, shape, the presence of calcification or haemorrhage, and intra-lesion necrosis were analysed. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were also calculated.

RESULTS

The PE/U ratio (≤1.25), CTu (≥32.2 HU), DEpeak (≤43.15 HU), DEPP (≤37.65 HU), presence of intralesional necrosis, location (bilateral adrenal glands), and irregular shape were significant variables for differentiating AMs from lipid-poor AAs (p<0.05). Among them, PE/U ratio (≤1.25) was of greater value in differentiating the two adrenal diseases, with sensitivity, specificity, area under the receiver operating curve (ROC) curve (AUC) of 92%, 84%, 0.933, respectively. When at least any three of above criteria were combined, the sensitivity, specificity, PPV, and NPV for diagnosing AMs were 88%, 93%, 88%, and 88%, respectively.

CONCLUSIONS

These seven CT criteria are conducive to differentiate AMs from lipid-poor AAs. Early biphasic contrast-enhanced CT is a high-efficient and practical imaging tool in differentiating them.

Non-secreting adrenal myelolipoma in a middle-aged male patient manifesting with sudden onset of severe lower back pain

Adrenal myelolipoma (AML) is a rare benign tumor, usually non-functioning and asymptomatic until it reaches large size. AML is mostly detected incidentally by imaging and is composed of adipose tissue and hematopoietic elements. Only symptomatic tumor needs surgical excision. We report the case of a large non-functioning adrenal tumor discovered by means of combined imaging techniques in a middle-aged male patient who complained the sudden onset of severe lower back pain; successful laparoscopic removal was performed, and AML was diagnosed at histopathology.

May hemocytometer parameters be a biomarker in distinguishing between adrenal adenomas and carcinomas and in prognosis of adrenocortical carcinomas?

Recently, studies have reported that inflammatory response and elevated platelet counts are associated with several cancers. In the present study, we aimed to evaluate hemocytometer parameters in differentiating adrenal adenoma and carcinoma, and the prognostic utility of hemocytometer parameters in adrenocortical carcinoma (ACC). We included 30 patients with nonfunctional adrenal adenoma and 13 patients with ACC having undergone surgery between 2005 and 2017 and followed up postoperatively at our centre. The neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), red blood cell distribution width (RDW), mean platelet volume (MPV) and plateletcrit (PCT) were evaluated preoperatively in all patients included in the study. There was a significant difference between the adrenal adenoma and ACC groups in terms of neutrophil and lymphocyte counts, NLR and PLR. There was no significant difference between the two groups in terms of platelet count and MPV, but PCT levels were significantly lower in ACC group. There was no statistically significant difference between recurrent and/or metastasis positive patients and negative ones according to NLR, PLR, RDW and MPV. There was a statistically significant difference in RDW levels and tumor diameter between the groups. Our study is the first to evaluate hemocytometer parameters in differentiating adrenal adenomas and carcinomas, and also in the prognosis of ACC. The present study suggested that the hemocytometer parameters may be a marker in the differential diagnosis of adrenal adenomas and carcinomas. However, our study also showed that these parameters had no prognostic value in ACC.

Characteristic CT features of pheochromocytomas - probability model calculation tool based on a multicentric study

OBJECTIVES

The aim of the study was to evaluate the CT features of adrenal tumors in an effort to identify features specific to pheochromocytomas and second, to define a feasible probability calculation model.

METHODS

This multicentric retrospective study included patients from the period 2003 to 2017 with an appropriate CT examination and a histological diagnosis of an adrenal adenoma, pheochromocytoma, adrenocortical carcinoma, or metastasis. In total, 346 patients were suitable for the CT image analysis, which included evaluation of the largest diameter, the shape of the lesion, the presence of central necrosis and its margins, and the presence of an enhancing peripheral rim ("ring sign").

RESULTS

Pheochromocytomas have a significantly more spherical shape (P<0.001), whereas an elliptical shape significantly reduces the probability of a pheochromocytoma (odds ratio = 0.015), as does another shape (odds ratio = 0.006). A "ring sign" is also more frequent in pheochromocytomas compared to other adrenal tumors (P=0.001, odds ratio = 6.49). A sharp necrosis also increases the probability of a pheochromocytoma more than unsharp necrosis (odds ratio 231.6 vs. 20.2). The probability calculation model created on the basis of the results confirms a high sensitivity and specificity (80% and 95%).

CONCLUSION

This study confirms the value of anatomical features in the assessment of adrenal masses with the ability to significantly improve the identification of pheochromocytomas. Advanced assessment of the tumor shape was defined and a original comprehensive calculating tool of the pheochromocytoma probability was created on the basis of the results presented here and could be used in clinical routine.

Ring opening of epoxides with [18F]FeF species to produce [18F]fluorohydrin PET imaging agents

A simple technique for the preparation of [18F]HF has been developed and applied to the generation of an [18F]FeF species for opening sterically hindered epoxides. This method has been successfully employed to prepare four drug-like molecules, including 5-[18F]fluoro-6-hydroxy-cholesterol, a potential adrenal/endocrine PET imaging agent. This easily automated one-pot procedure produces sterically hindered fluorohydrin PET imaging agents in good yields and high molar activities.

Surgery for adrenal angiomyelolipoma: an individualized concept

BACKGROUND

Because adrenal angiomyelolipoma (AAML) is rare and uniformly benign, the indications for surgery are ill defined.

METHODS

Among a series of 156 patients with adrenal pathologies surgically treated between 2013 and 2018, 12 patients were operated with the diagnosis of an AAML. The clinical as well as imaging parameters forming the individual indications for surgery were analyzed.

RESULTS

Preoperative diagnosis consistent with AAML was made in all 12 patients. The mean size of surgically removed AAML was 82.3 mm (45-150 mm). Gender and affected side were evenly distributed. Local symptoms but lack of radiological signs suspicious for malignancy or size increase were observed in 4 of 12 patients (group 1, 33%). In contrast, 4 of 12 patients (group 2, 33%) showed radiological signs suspicious for malignancy but lacked local symptoms. Additional 4 of 12 patients (group 3, 33%) showed both local symptoms and radiological signs suspicious for malignancy. Patients with local symptoms harbored significantly larger tumors compared to those patients that lacked local symptoms (93.9 mm ± 32.8 vs. 59.3 mm ± 2.7, p = 0.021). Patients with radiologically suspicious signs were older (60 years ± 9.9 vs. 53 years ± 5.4, p > 0.05), and time to surgery was shorter (4.4 months ± 3 vs. 6.0 months ± 3.0, p > 0.05). Importantly, surgical approach was not influenced by tumor size (p = 0.65). However, patients with suspicious imaging were more likely to be operated by conventional open approach (4 of 8 vs. 0 of 4, p = 0.08). The minimal invasive approach was associated with shorter hospital stay (7 days, ± 1.3 vs. 14.2 days, ± 8.8, p = 0.038). All lesions that showed radiological signs suspicious for malignancy proved benign in final histology.

CONCLUSION

Large AAML present a clinical challenge. The presence of local symptoms and/or radiological signs suspicious for malignancy identifies three groups of patients that define the concept of an individualized indication for surgery in AAML. A minimal invasive approach can be advocated even for large AAML with radiological signs suspicious for malignancy.

A rare case of co-existing adrenal and pelvic myelolipomas

We are reporting a case of co-existing left sided pelvic and right sided adrenal myelolipomas in a 68-year-old male patient. Both lesions were incidentally discovered on CT whilst undergoing a staging scan for suspected urinary bladder cancer. The patient had a background of hypertension and type 2 diabetes. Contrast enhanced CT scan showed both lesions to be of mixed fat and soft tissue density. Given the size, location, and attenuation characteristics of the pelvic mass, retroperitoneal liposarcoma was thought to be a differential diagnosis, prompting the decision for an elective CT-guided biopsy. Both masses were targeted successfully using core biopsy needles. Subsequently, histopathology results for both the right adrenal and the left pelvic masses showed features compatible with myelolipomas. The right retroperitoneal mass was compatible with an adrenal myelolipoma and left pelvic mass was deemed as an extra-adrenal myelolipoma (EAML).

Adrenal myelolipoma: a comprehensive review

INTRODUCTION

Adrenal myelolipoma is an invariably benign neoplasm of the adrenal gland that is the second most common primary adrenal incidentaloma following adrenocortical adenomas. It is composed of elements of adipose tissue and extramedullary hematopoiesis. Hypotheses on stem cells and hormonal factors have been formulated regarding its pathogenesis that is still obscure. Despite its benign behavior, adrenal myelolipoma is clinically relevant as it might cause significant difficulties in the differential diagnosis of adrenal tumors.

METHODS

We have reviewed 420 cases reported between 1957 and 2017 on adrenal myelolipoma retrieved from PubMed and Scopus databases and also 20 of our case series to provide a comprehensive analysis of their pathology, epidemiological and clinical features.

RESULTS AND CONCLUSIONS

The average age for its diagnosis was 51 years, and no gender difference was observed. The average size of tumors was 10.2 cm. Congenital adrenal hyperplasia was associated to 10% of all cases analyzed, while other adrenal hypersecretory disorders (cortisol, aldosterone) were found in 7.5% of cases. Computed tomography and magnetic resonance imaging can be reliably used for its differential diagnosis. If the diagnosis of an adrenal myelolipoma is unambiguous, and no associated symptoms or hormonal activity are established, surgical intervention is usually not necessary.