With the widespread use of imaging techniques (ultrasound, CT and MRI) and the popularity of health checkups, the detection rate of adrenal masses has increased greatly. An unexpected adrenal tumor is an adrenal mass that is not clinically associated with any endocrine symptoms or signs, but is only detected during abdominal imaging examinations for other reasons. The incidence of adrenal tumors is about 1.4% to 2.0%, which is still relatively common. Patients often feel nervous and anxious when they encounter such cases, mainly worrying about whether the tumor is good or bad and whether it needs surgery. When faced with an unexpected adrenal tumor, there is no need to make a fuss, nor should we take it lightly. The following two aspects should be evaluated under the guidance of doctors: 1. Whether the adrenal accidental tumor has endocrine function. If the blood and urine cortisol levels are elevated and cannot be suppressed by small doses of dexamethasone, consider the possibility of subclinical cortisolism (Cushing’s syndrome); if the blood and urine aldosterone are elevated, renin activity is suppressed, and blood aldosterone levels are not suppressed by saline, consider the possibility of primary aldosteronism; if the blood and urine catecholamine and intermediate metabolite levels are elevated, consider the possibility of silent pheochromocytoma; if androgen or estrogen levels are significantly elevated, consider masculinizing or feminizing adrenal tumors. All functional adrenal accidental tumors, regardless of their benign or malignant nature, need to be surgically removed. 2. Whether the adrenal accidental tumor is benign or malignant. Malignant ones definitely need surgery, while benign non-functional ones only need regular follow-up. Adrenal tumors include almost all adrenal tumors and non-neoplastic lesions, such as adenoma, aldosterone tumor, adrenocortical carcinoma originating from the adrenal cortex, pheochromocytoma and ganglion cell tumor originating from the adrenal medulla, medullary lipoma and non-neoplastic cysts originating from the adrenal stroma, in addition, metastases from malignant tumors to the adrenal gland and lymphoma originating from the adrenal gland can be manifested as adrenal tumors. In addition, metastases from malignant tumors to the adrenal glands and lymphomas originating from the adrenal glands can be manifested as adrenal tumors. Ultrasound, CT and MRI of the adrenal gland are of great value in the differential diagnosis of benign and malignant masses. Adrenal adenomas are characterized on CT as low-density soft tissue masses due to their lipid-rich nature; adrenocortical carcinomas are characterized on CT as large masses with heterogeneous density and partial calcification; pheochromocytomas are usually larger than adenomas and show heterogeneous enhancement and may Pheochromocytoma is usually larger than adenoma and shows inhomogeneous enhancement with necrosis, cystic changes or hemorrhage; adrenal metastases and lymphoma may appear as uniform soft tissue density masses in one or both adrenal glands, which are sometimes difficult to distinguish. A history of primary tumor (e.g., lung cancer) mostly supports the diagnosis of metastatic tumor, and significantly elevated blood lactate dehydrogenase (LDH) and urine β2 microglobulin contribute to the diagnosis of adrenal lymphoma. Mass size: larger masses (>5 cm in diameter) have a higher possibility of malignancy and surgical resection is recommended; for masses <3 cm in diameter and non-functional, CT follow-up is recommended; for masses between the two, most of them are non-functional adrenal adenomas. If it is difficult to distinguish them from metastases and cortical carcinomas after multiple examinations, percutaneous adrenal mass aspiration biopsy is required, and if biopsy is still insufficient to distinguish If the biopsy is not sufficient to distinguish benign from malignant, it should be removed surgically. In conclusion, accidental adrenal tumors are relatively common, involving multiple diseases and complicated differential diagnosis. Preoperative evaluation is extremely important and is a systematic project, therefore, it is better to be hospitalized for examination.