Adrenal Pseudocyst
An adrenal pseudocyst is a fluid-filled or blood-containing cavity within or adjacent to the adrenal gland that does not have a true cellular lining. Most adrenal pseudocysts are thought to develop from prior adrenal hemorrhage, trauma, infection, or bleeding within an adrenal lesion. Most are benign and asymptomatic and are discovered incidentally on abdominal imaging. Less commonly, larger or complicated pseudocysts can cause abdominal or flank discomfort, or occasionally rupture or become infected. Imaging—particularly CT and MRI—is central to characterization, and most adrenal pseudocysts require little more than reassurance and, in selected cases, follow-up.
What is it?
The adrenal glands are two small triangular organs that sit on top of the kidneys. They produce hormones that regulate stress responses, metabolism, blood pressure, and salt and water balance. An adrenal cyst is a fluid-filled lesion within or adjacent to the adrenal gland. Adrenal cysts are broadly divided into several categories based on their internal features: true epithelial cysts, endothelial cysts (such as lymphangiomas), parasitic cysts (most commonly caused by Echinococcus species), and pseudocysts. Adrenal pseudocysts differ from “true” cysts in that they do not have an inner cellular lining. They are usually surrounded by a fibrous wall and often contain fluid, blood products, or debris. Pseudocysts are the most common type of adrenal cystic lesion identified in adults.
Adrenal pseudocysts are generally thought to develop as a long-term consequence of prior bleeding or injury within or adjacent to the adrenal gland. Recognized contributors include prior adrenal hemorrhage from any cause (such as trauma, severe infection, anticoagulation, clotting disorders, or complications of pregnancy or surgery), infection or inflammation of the adrenal gland, and bleeding within an underlying adrenal lesion. In some cases, the original underlying process is not obvious by the time the pseudocyst is identified, and the lesion is discovered years later as a relatively stable, thin-walled, cystic finding on imaging.
Adrenal pseudocysts vary widely in size. Many are small and asymptomatic and are discovered incidentally on abdominal imaging performed for unrelated reasons. Larger pseudocysts may reach several centimeters or more and can occasionally produce upper abdominal, flank, or back discomfort, a sense of fullness, or—rarely—symptoms related to pressure on nearby organs. Complications of adrenal pseudocysts are uncommon but can include acute bleeding into the pseudocyst, infection (which can produce a functional abscess), or rupture, particularly in larger lesions or after trauma.
Adrenal pseudocysts are typically nonfunctional, meaning they do not produce hormones. However, some pseudocysts can develop within or adjacent to underlying adrenal lesions—including benign adrenal adenomas, adrenal cortical carcinomas, or pheochromocytomas—that do produce hormones or that carry other clinical implications. When a cystic-appearing adrenal lesion is identified, particularly when features are atypical, it is important to consider whether it may represent bleeding within a hormone-producing or malignant lesion rather than a simple pseudocyst.
Evaluation is generally based on imaging, sometimes supplemented by targeted blood tests. Imaging usually starts with CT of the abdomen, ideally with and without intravenous contrast, which can characterize the lesion’s density, size, wall thickness, presence of internal calcifications or septations, and enhancement pattern. Simple adrenal pseudocysts are typically well-defined, thin-walled, low-density lesions with little or no internal enhancement. MRI with contrast provides excellent characterization, particularly when there is diagnostic uncertainty; it can help distinguish simple pseudocysts from complex lesions, cystic adrenal tumors, and hemorrhagic components at different stages of evolution. Ultrasound may occasionally identify adrenal pseudocysts but is generally less useful than CT and MRI for detailed characterization.
Blood tests to assess adrenal hormone function are commonly considered, particularly in patients with any concerning imaging features, in larger lesions, or in patients with signs or symptoms that might suggest a hormone-producing lesion. Tests may include morning cortisol and other cortisol-related studies, plasma or urine metanephrines (to help exclude pheochromocytoma), aldosterone and renin levels, and dehydroepiandrosterone sulfate (DHEA-S). Pheochromocytoma is particularly important to consider before any invasive intervention, because biopsy or manipulation of a pheochromocytoma can trigger a dangerous release of hormones.
Image-guided sampling of adrenal pseudocysts is generally avoided when a confident diagnosis can be made from imaging and hormonal evaluation. It is reserved for unusual situations in which imaging findings are atypical, malignancy cannot be reasonably excluded, or infection is suspected, and it is performed only after appropriate hormonal evaluation.
Important to Know
For the great majority of patients with adrenal pseudocysts, no specific treatment is needed. Once the diagnosis is confidently established by imaging and hormonal evaluation, most small, simple, asymptomatic pseudocysts can be managed with reassurance and—in selected cases—periodic follow-up imaging to confirm stability. Many small, stable lesions do not require any further follow-up once the diagnosis is clear, while larger or less typical lesions may be monitored with periodic imaging for a defined time.
Lifestyle changes are generally not needed for typical adrenal pseudocysts. Patients can usually maintain normal diet, exercise, and activity levels without restriction. There is no need to avoid specific foods or activities solely because of an adrenal pseudocyst, although general healthy habits remain important for overall health.
Treatment is considered in selected situations. These typically include pseudocysts that cause significant and persistent symptoms not explained by other conditions; large or rapidly enlarging lesions; complications such as bleeding, infection, or rupture; lesions where the diagnosis is uncertain and malignancy cannot be confidently excluded; and lesions in which an underlying hormone-producing or malignant adrenal tumor cannot be reasonably excluded. When treatment is needed, adrenalectomy (surgical removal of the adrenal gland containing the lesion) is generally the preferred approach, most often performed laparoscopically or through minimally invasive techniques by surgeons with adrenal experience. Adrenal-preserving surgical approaches may be considered in selected cases, and decisions are individualized in collaboration with endocrine or hepatobiliary surgeons and endocrinologists.
Before any planned surgery, biopsy, or interventional procedure involving the adrenal gland, appropriate hormonal evaluation—particularly exclusion of pheochromocytoma—is essential because manipulation of a pheochromocytoma can produce a dangerous surge of hormones and a hypertensive crisis. Coordination with endocrinology helps ensure that appropriate testing and, when necessary, preoperative medications are used to minimize risk.
Patients who undergo unilateral adrenalectomy typically retain normal adrenal function through the remaining gland and do not require long-term hormone replacement. Patients who develop adrenal insufficiency from any cause—including surgery involving both glands or extensive bilateral disease—require hormone replacement with glucocorticoids and, when needed, mineralocorticoids, along with education about stress dosing during illness, injury, or surgery.
For patients with adrenal pseudocysts that are being monitored, awareness of warning signs of complications is important. Any new or worsening abdominal pain, signs of infection, or acute symptoms warrant medical evaluation. Documentation of the diagnosis in the medical record helps ensure that the finding is not misinterpreted on future imaging and that appropriate consideration is given if new imaging or interventions are planned in the future.
Care is typically coordinated by primary care clinicians and, when relevant, radiologists, endocrinologists, and endocrine or hepatobiliary surgeons. Imaging and laboratory findings are interpreted alongside the patient’s symptoms, examination, and broader clinical context rather than in isolation.
Although a typical adrenal pseudocyst is almost always benign and asymptomatic, any new abdominal symptoms should be evaluated based on their own clinical features rather than automatically attributed to a previously identified lesion. Coexisting conditions—such as kidney disease, other abdominal disorders, or, rarely, malignancy—can occur and should be considered.
Red flag symptoms include sudden severe upper abdominal, flank, or back pain (especially after trauma to the abdomen), lightheadedness or fainting, rapid heart rate, cool clammy skin or signs of shock, high fever with chills (which may suggest infection of the lesion), severe vomiting with abdominal pain, sudden severe hypertension with headache or palpitations (which may suggest an underlying hormone-producing lesion), or signs of severe infection. These warrant prompt or urgent medical evaluation, as they may indicate bleeding, rupture, infection, or other serious complications.