“ For indeterminate adrenal masses identified at dual-phase IV contrast-enhanced CT, higher enhancement during the arterial phase, arterial phase enhancement levels greater than 110HU, and lesion heterogeneity should prompt consideration of pheochromocytoma.”
MDCT of Adrenal Masses: Can Dual-Phase Enhancement Patterns Be Used to Differentiate Adenoma and Pheochromocytoma?
Northcutt BG, Raman SP, Long C, Oshmyansky AR, Siegelman SS, Fishman EK, Johnson PT
AJR 2013; 201:834-839

“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.”
Management of incidental adrenal nodules: a survey of abdominal radiologists conducted by the Society of Abdominal Radiology Disease‐Focused Panel on Adrenal Neoplasms 
Michael T. Corwin et al.
Abdominal Radiology (2022) 47:1360–1368

Management of incidental adrenal nodules: a survey of abdominal radiologists conducted by the Society of Abdominal Radiology Disease‐Focused Panel on Adrenal Neoplasms
Michael T. Corwin et al.
Abdominal Radiology (2022) 47:1360–1368

“The majority of respondents either rarely or never rec- ommend hormonal evaluation or endocrinology consultation when describing an adrenal incidentaloma. Both the American Association of Clinical Endocrinologists and the European Society of Endocrinology recommend hormonal evaluation to determine the functional activity in all patients with adrenal incidentalomas. The 2017 ACR white paper advises consideration for biochemical evaluation for most incidentalomas as adrenal hyperfunction may not be clinically evident."
Management of incidental adrenal nodules: a survey of abdominal radiologists conducted by the Society of Abdominal Radiology Disease‐Focused Panel on Adrenal Neoplasms 
Michael T. Corwin et al.
Abdominal Radiology (2022) 47:1360–1368

“It may be impossible to distinguish a large atypical adenoma from an ACC or other malignant mass with imaging because of overlapping imaging features. If there are no benign diagnostic features, evaluation of the clinical context, including hormonal assessment, is essential for assessing the need for surgical resection of a 4-cm or larger adrenal mass. Patients with a large adrenal mass should be managedby a multidisciplinary team that includes surgeons, endocrinologists, and radiologists.”
Adrenal Neoplasms: Lessons from AdrenalMultidisciplinary Tumor Boards
Ryan Chung et al.
RadioGraphics 2023; 43(7):e220191 July 2023

“Most patients with adrenal cysts are asymptomatic; however, 10% present with symptoms of mass effect such as abdominal pain or discomfort. In a large series of adrenal cysts published in 2022, the median size at the time of initial diagnosis was 4.8 cm, ranging from 0.5 cm to 20 cm. In older studies, which included a higher proportion of patients who underwent surgery, the average cyst size was 4.7–9.6 cm Surprisingly, larger cysts (>5 cm) are more common in younger patients, with a median age of 37 years versus 51 years in patients with cysts <5 cm. The prevalence of symptoms of mass effect in patients with cysts >5 cm is 20%, which is tenfold higher than in patients with cysts <5 cm (2%). Bilateral adrenal cysts occur in 3–8% of patients andunilateral lesions show equal left and right distribution.”
Adrenal cysts: an emerging condition
Jan Calissendorff et al.
Nature Reviews Endocrinology 2023 (in press)

“In the absence of symptoms or functionality, the best management strategy for adrenal cysts is not clear. When a cyst is accidentally discovered and with clearcut benign imaging characteristics, whether the patient should undergo follow-up imaging for detection of growth is also not clear. In addition, the ideal frequency and length of followupfor such imaging are unknown. Most benign adrenal cysts are asymptomatic, but they may grow and give rise to symptoms of mass effect. The predictors of growth or potential haemorrhage are unclear and thus monitoring should be individualized. The pathogenic drivers behind the development of adrenal cysts and growth are also incompletely understood.”
Adrenal cysts: an emerging condition
Jan Calissendorff et al.
Nature Reviews Endocrinology 2023 (in press)

“Because the attenuation of simple fluid is less than or equal to 10 HU, a homogeneousunilocular cystic adrenal lesion can mimic adenoma at nonenhancedCT. Owing to their central hypoattenuation, cysts and pseudocysts may also mimic pheochromocytomas with cystic and/or necrotic change. A key feature of an adrenal cyst is its lack of enhancement.”
Adrenal Neoplasms: Lessons from AdrenalMultidisciplinary Tumor Boards
Ryan Chung et al.
RadioGraphics 2023; 43(7):e220191 July 2023

“Myelolipomas contain macroscopic fat, which is characterized by attenuation of less than −20 HU on CT and signal dropout on fat-suppressed MRI sequences . Macroscopic fat rarely can be seen in adrenal adenomas, adrenocortical carcinomas (ACCs), and pheochromocytomas, and large myelolipomas may be difficult to distinguish from liposarcomas .”
Adrenal Incidentalomas: Clinical Controversies and Modified Recommendations 
Garrett RW et al
AJR 2016; 206:1170–1178

Change over time

• remain stable
• enlarge
• get smaller

Complications can be due to

• mass effect
• hemorrhage

“ The most common imaging features include a 2-3 cm oval hematoma, irregular hemorrhage obliterating the adrenal gland, periadrenal hemorrhage or fat stranding, and uniform adrenal swelling with increased attenuation.”
Imaging of traumatic adrenal injury
To’o KJ, Duddalwar VA
Emerg Radiol (2012) 19:499-503