Management of Enlarging Adrenal Nodules

Initial Assessment and Growth Rate Determination

Adrenalectomy should be considered for any adrenal nodule growing >5 mm/year after repeating functional work-up, as this growth rate indicates potential malignancy regardless of initial imaging characteristics 1, 2, 3
For nodules with a growth rate of >5 mm/year, proceed directly to surgical evaluation after repeating hormonal work-up 1, 2, 3, 4
For nodules with a growth rate of 3-5 mm/year, continue surveillance with repeat imaging in 6-12 months 4, 5
For nodules with a growth rate of <3 mm/year, no further imaging or functional testing is required 1, 2, 3, 4

Before any surgical decision for an enlarging nodule, repeat the complete hormonal work-up, including a 1 mg dexamethasone suppression test for autonomous cortisol secretion, aldosterone-to-renin ratio if hypertension or hypokalemia is present, plasma or 24-hour urinary metanephrines if the nodule is >10 HU on non-contrast CT or if there are signs of catecholamine excess, and serum androgen testing if virilization signs are present 1, 2, 3
Obtain updated imaging to reassess malignancy risk, using non-contrast CT to measure current Hounsfield units (HU), and consider washout CT or chemical shift MRI if the nodule is indeterminate (>10 HU) 1, 2, 3, 6

Minimally-invasive adrenalectomy can be offered for suspected adrenocortical carcinoma if the tumor can be safely resected without rupturing the capsule 1, 2, 3
Open adrenalectomy should be considered for larger tumors or those with locally advanced features, lymph node metastases, or tumor thrombus 1, 2, 3
Adrenal mass biopsy should not be performed routinely for enlarging nodules, but may be considered if diagnosis of metastatic disease from extra-adrenal malignancy would change management, and must exclude pheochromocytoma biochemically before any biopsy attempt 1, 2, 3, 6

Nodules ≥4 cm, even if radiologically benign, warrant surgery if growth >5 mm/year due to higher baseline malignancy risk 1, 4, 5
Do not rely solely on initial benign imaging characteristics if the nodule is enlarging significantly, and do not delay surgical evaluation for nodules growing >5 mm/year while waiting for additional imaging 1, 2, 3, 6
Do not assume bilateral nodules represent metastatic disease, and do not proceed with surgery without first excluding pheochromocytoma biochemically to avoid intraoperative hypertensive crisis 1, 2, 3, 7