The adrenal gland is an important endocrine organ in the human body, located in the upper part of the kidney, which can secrete life-saving hormones such as epinephrine and norepinephrine, as well as hormones that maintain human metabolism such as glucocorticoids, salt corticoids and sex hormones. Once a tumor occurs in one part of the adrenal gland, the secretion of hormones in the corresponding part will be disrupted, thus affecting our normal life. However, it is important to tell you that there are 10 types of adrenal tumors that can be cystic. The 10 adrenal tumors can be cystic. a. Adrenal cysts Adrenal cysts are mostly round or oval, with thin and smooth walls, and the contents of the cyst are usually liquid components. the CT performance is mostly uniform hypointense, and the MRI is uniform long T1 and long T2 signal, the signal changes with the change of the cyst contents, such as intracapsular hemorrhage, T1 and T2 can be high signal; enhanced scan has no obvious enhancement of the cyst wall and the cyst. In contrast, when pseudocyst or true cyst is combined with infection, the cyst wall may be thicker, and the cyst wall may be enhanced on enhancement scan. Speckled and arcuate calcification can be seen, and calcification of the cyst wall. Calcifications in the cyst wall or within the cyst are more characteristic for the qualitative diagnosis of adrenal cysts, especially intracapsular calcifications are more reliable signs of true adrenal cysts. Cystic lymphadenoma of adrenal gland is composed of dilated lymphatic ducts with lymphatic stroma and smooth endothelium; CT shows cystic hypodense shadow with visible septa; about 15% of cystic lymphadenoma can be seen as needle-like, plaque, short rod-like and irregular calcification; enhanced scan, especially delayed scan, can clearly show septa. The CT value of cystic lymphangiectasia depends on the composition of the cystic fluid. If the cyst contains more lipids, the density is relatively low, while the density is relatively high when the cystic fluid contains more protein. C. Adrenal teratoma Adrenal teratoma is a residual tumor of embryonic origin, mostly containing 2 or 3 germ layers of tissue. The cyst is mainly composed of keratinized material, cartilage, teeth, sebum and hair. Calcification is a characteristic CT manifestation of adrenal teratoma, mostly showing speckled, arcuate or eggshell-like calcification. Fatty density or signal is another typical imaging manifestation. The parenchymal part of the enhancement scan is mildly enhanced, the envelope and separation of the mass are significantly enhanced, and the cystic part is not enhanced. IV. Adrenal hematoma Adrenal hematoma has traumatic and non-traumatic causes. Initially, the hematoma shows high density on CT with a CT value of 50-90 HU. As the hematoma is absorbed, follow-up usually reveals a gradual decrease in density approaching watery density. The MRI presentation of an adrenal hematoma can reflect the evolution of hemoglobin from acute to chronic degradation. The acute phase of the hematoma shows a heterogeneous signal on both T1WI and T2WI, and the signal is often low on T2WI due to the association with intracellular deoxygenated hemoglobin. After about 1 week, ferrous hemoglobin oxidizes to methemoglobin and the hematoma shows high signal on both T1WI and T2WI. Benign hematoma images will gradually decrease in size with follow-up hematoma. If the hematoma is not completely absorbed, the imaging features resemble a cyst with no enhancement on enhancement scans, but peripheral circumferential enhancement can occur when vascular fiber wrapping is formed. Benign pheochromocytoma tumors are mostly round or oval with clear borders, often with hemorrhage, necrosis and cystic changes, and rich blood supply; malignant pheochromocytoma tumors are irregular in shape, with more solid components, irregular necrotic areas and blurred borders, and invade surrounding organs. MRI signal is heterogeneous, T1WI shows equal or slightly low signal, similar to muscle; T2WI mostly shows heterogeneous low, medium or high signal. Adrenocortical adenoma is a benign tumor of the adrenal cortex, which is divided into functional and nonfunctional. The large amount of intracellular lipids in adenomas is reflected by the corresponding attenuation of signal intensity on chemical shift images, which can be used to quantify the lipids in adenomas. Neuroblastoma originates from sympathetic nervous system tissues and occurs mostly in children, about 60% of patients are <2 years old. CT tumors are usually large, with poorly defined borders and uneven density. T1WI tumor signal is slightly lower than that of the liver and renal medulla, and T2WI tumor signal is higher than that of the liver and similar to that of the kidney. The signal inhomogeneity within the tumor is due to intratumoral hemorrhage and necrosis. Adrenocortical adenocarcinoma is a rare and aggressive malignant tumor that occurs in children and 30-50 years old, with a bimodal age of onset. It is common to see sand-like calcification in the central area of the tumor. The CT value of non-necrotic area is 45-75HU in plain scan, with high density, and the CT value of necrotic area is 15-20HU, and the parenchymal part of the tumor is rapidly and inhomogeneously intensified in arterial phase in enhancement scan, and continuously intensified in delayed phase. "This is due to the large size of the mass and the fact that the blood flow in the tumor is very large. This is because of the huge size of the mass, rich blood supply, and the presence of a large number of blood sinus-like interstitial components between the tumor nests, so it shows progressive intensification. Adrenal neurofibroma Adrenal neurofibroma is a benign tumor derived from mesenchymal tissue, which can occur in any part of nerve endings or along the nerve trunk, more common in skin and subcutaneous tissue, and rarer in adrenal gland. Adrenal metastases are the most common site of metastatic tumors, and nearly 1/4 of patients with malignant epithelial tumors have adrenal metastases in autopsy. Common primary tumors include lung cancer, breast cancer, kidney cancer and melanoma. The metastases are large in size, most of them are >2 cm, with irregular margins, often with necrosis and invasion of surrounding structures. The normal adrenal gland is often not visible on the ipsilateral side of the tumor, and the density and signal of CT and MRI are not uniform.