Adrenal Cyst
A fluid-filled sac in or on an adrenal gland
Quick Facts
- Type: Endocrine (adrenal) growth
- Usual nature: Benign and non-functioning
- Often found: Incidentally on CT or ultrasound
- Treatment: Monitoring; surgery if large or symptomatic
Overview
An adrenal cyst is a fluid-filled sac that develops within or on the surface of an adrenal gland, the small hormone-producing gland that sits above each kidney. Adrenal cysts are relatively uncommon and are usually benign. Most are discovered by accident when a person has imaging for an unrelated reason, in which case they may be referred to as an incidental adrenal mass.
Most adrenal cysts cause no symptoms and do not affect hormone production. Larger cysts or those with unusual features may need closer evaluation to confirm they are not cancerous and to decide whether treatment is needed. These growths are distinct from solid adrenal tumors.
Symptoms
Small adrenal cysts typically cause no symptoms at all. When a cyst grows large, it may press on nearby structures and cause:
- A dull ache or fullness in the side, flank, or upper abdomen
- A feeling of pressure or a palpable lump in larger cysts
- Nausea or early fullness after eating if a large cyst presses on the stomach
- Back pain in some cases
Rarely, a cyst may bleed or become infected, causing sudden, more severe pain that needs prompt evaluation. Most adrenal cysts do not produce hormones, so symptoms of hormone excess such as high blood pressure or unexplained weight change are unusual. Because small cysts are silent, many are found only when a scan is done for an unrelated reason, and a person may have had the cyst for a long time without knowing it.
Causes
Adrenal cysts are grouped by what they are made of and how they form.
- Endothelial (lymphangiomatous) cysts: Arising from blood or lymph vessel tissue, among the most common types.
- Pseudocysts: Forming after bleeding into the gland, sometimes following injury.
- Epithelial cysts: Lined by gland-type cells.
- Parasitic cysts: Caused rarely by infections such as echinococcosis.
In many cases the exact reason a cyst forms is not known. Trauma and prior bleeding into the gland are recognized contributors to pseudocysts.
Risk Factors
- Previous injury or bleeding involving the adrenal gland (for pseudocysts)
- Certain parasitic infections in some regions
- Adrenal cysts can occur at any age but are more often noticed in adults
- Undergoing abdominal imaging, which increases the chance of incidental discovery
Diagnosis
Imaging is the main way adrenal cysts are found and characterized, with hormone testing to confirm they are not active.
- CT scan: Shows the size, wall thickness, and contents of the cyst and helps distinguish simple cysts from worrisome masses.
- MRI: Provides detailed soft-tissue images and helps clarify uncertain cases.
- Ultrasound: Can confirm a fluid-filled structure.
- Hormone tests: Blood and urine tests check that the cyst is not producing excess adrenal hormones.
- Follow-up imaging: Repeat scans over time can confirm a cyst is stable and not changing.
Treatment
Treatment depends on size, features, symptoms, and whether the cyst is producing hormones.
- Observation: Small, simple, symptom-free cysts are usually monitored with periodic imaging.
- Surgery: Removal of the cyst or adrenal gland may be advised for large cysts, those causing symptoms, or any with features suggesting they could be cancerous.
- Drainage: Occasionally a cyst is drained, though surgery is often preferred for definitive treatment.
An endocrinologist or surgeon helps decide the safest approach based on the individual cyst's characteristics. When surgery is performed, it can often be done using minimally invasive (laparoscopic) techniques, which involve small incisions and a quicker recovery. If only one adrenal gland is removed, the other usually takes over hormone production without the need for lifelong replacement. The overall outlook for benign adrenal cysts is very good, and most people who have one treated or monitored do not have further problems. Because incidental adrenal masses are increasingly found as imaging becomes more common, doctors follow a careful process to separate harmless cysts from the small number that need closer attention.
When to See a Doctor
If a doctor finds an adrenal cyst, follow recommended monitoring and hormone testing. Contact your doctor if you develop:
- New or worsening pain in the side, back, or abdomen
- A noticeable lump or persistent fullness
- Symptoms of hormone changes such as high blood pressure, weight changes, or excess hair growth
- Sudden, severe pain, which may signal bleeding or infection and warrants urgent care
Frequently Asked Questions
Are adrenal cysts cancerous?
Most adrenal cysts are benign and not cancerous. A small number may have features that need further evaluation to be sure. Imaging and, when needed, surgery help confirm the nature of the cyst.
Do adrenal cysts need to be removed?
Not usually. Small, simple, symptom-free cysts are often just monitored with periodic scans. Removal is considered for large cysts, those causing pain, or any with suspicious features or hormone activity.
Can an adrenal cyst affect my hormones?
Most adrenal cysts do not produce hormones and have no effect on hormone levels. Doctors typically run blood and urine tests to confirm this. If a cyst is found to be hormonally active, treatment may be recommended.
What causes an adrenal cyst to form?
Causes include abnormal blood or lymph vessel tissue, bleeding into the gland after injury, and, rarely, parasitic infection. In many cases the exact cause is not known. The type of cyst influences how it is managed.
When is an adrenal cyst an emergency?
Sudden, severe pain in the side or abdomen can occasionally signal bleeding into the cyst or infection. These situations need prompt medical evaluation. Routine, painless cysts found on a scan are not emergencies.
References
- National Cancer Institute (NCI). Adrenocortical Carcinoma Treatment.
- Mayo Clinic. Adrenal masses.
- MedlinePlus, U.S. National Library of Medicine. Adrenal gland disorders.