It seems to me you should have a follow up to have it evaluated as you had cancer surgery previously.
From the web:
Adrenal adenomas are benign (non-cancerous) tumours of the adrenal gland. They arise from the outer layer of the gland, called the adrenal cortex.
The adrenal cortex normally makes hormones that belong to the steroid family.
If an adrenal adenoma produces hormones, it is called 'functioning', though this term makes them sound healthy when in fact such adenomas often produce excessive amounts of steroid hormones.
If an adenoma does not produce a hormone it is termed 'non-functioning'.
Adrenal adenomas are often found by chance during a scan of the body for an unrelated condition. However, all adrenal masses (lumps) need careful evaluation to ascertain their nature, especially to see whether they are producing hormones.
If an adrenal adenoma that is producing hormones is not treated, it can have serious consequences
More rarely, a mass in the adrenal gland is cancer that has spread from another part of the body, usually the lung or bowel (ie 'metastatic' cancer).
Generally, the origin of the cancer is clear from the clinical examination or from simple tests such as a chest X-ray.
In addition, the CT or MRI appearance of metastatic cancer in the adrenal gland can be distinguished from a benign adrenal adenoma by use of specialised radiology.
An adrenal mass might also be a cancer of the adrenal cortex (adrenocortical carcinoma). Although they are very rare, these cancers are often large and can produce a combination of hormones.
Adrenal masses can also arise from the inner part of the adrenal gland, called the adrenal medulla, which is part of the nervous system and produces the 'fight-or-flight' hormones adrenaline and noradrenaline.
Tumours of the adrenal medulla are called phaeochromocytomas, and they also can be distinguished from adenomas by specialised scanning techniques as well as by blood and urine tests for adrenaline and noradrenaline.
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