Adrenal Cyst
An adrenal cyst is a fluid-filled sac that forms within or around one of the adrenal glands, which sit on top of the kidneys. Most adrenal cysts are benign and discovered incidentally during imaging performed for other reasons. They can vary in size and type, including simple cysts, endothelial cysts, pseudocysts, and cystic tumors. Most cause no symptoms unless they grow large or press on nearby structures.
What is it?
An adrenal cyst is a fluid-filled lesion that develops within the adrenal gland or the surrounding tissue. These cysts may form from developmental abnormalities, previous bleeding, inflammation, or vascular issues. Types of adrenal cysts include simple epithelial cysts, endothelial cysts (lymphangiomas), pseudocysts, and cystic neoplasms. Most are benign, but some cystic tumors can appear similar and require careful evaluation.
Imaging helps determine whether the cyst is simple or complex. CT and MRI provide information about the cyst’s size, wall thickness, internal contents, and relationship to nearby organs. Simple cysts have thin walls and clear fluid, while complex cysts may contain debris, septations, or calcifications that require closer follow-up.
Important to Know
Most adrenal cysts do not produce hormones and do not affect adrenal function. However, very large cysts can cause discomfort or compress surrounding structures. Rarely, cysts may become infected, bleed internally, or represent a cystic form of an adrenal tumor, which may need treatment.
Red flag symptoms include sudden severe abdominal or flank pain, fever, lightheadedness, or symptoms of internal bleeding. Follow-up imaging may be recommended to ensure the cyst remains stable and does not develop features concerning for a tumor.