Follow-up for Stable 2.6 cm Adrenal Mass
No further imaging or functional testing is required for this stable 2.6 cm adrenal mass, as it is below 4 cm and has demonstrated stability on interval imaging. 1
Rationale for No Further Follow-up
The 2023 CUA/AUA guidelines explicitly state that patients with benign non-functional adenomas less than 4 cm do not require further follow-up imaging or functional testing once initial characterization is complete. 1 Your mass at 2.6 cm falls well below this threshold, and the documented stability on interval imaging further confirms its benign nature.
Key Assumptions That Must Be Met
Before discontinuing surveillance, verify the following criteria were satisfied during initial workup:
Radiological benignity confirmed: The mass should demonstrate Hounsfield units ≤10 on non-contrast CT, indicating a lipid-rich adenoma. 1 If the initial CT was contrast-enhanced only, a non-contrast CT or washout study should have been performed to confirm benign characteristics. 1
Hormonal screening completed: All adrenal incidentalomas require initial biochemical evaluation regardless of imaging appearance, including 1 mg dexamethasone suppression test for autonomous cortisol secretion, aldosterone-to-renin ratio if hypertension or hypokalemia present, and plasma/urinary metanephrines if the mass showed >10 HU or signs of catecholamine excess. 1, 2
Stability documented: The report indicates "no significant interval change," which satisfies the requirement that growth is <3 mm/year—the threshold below which no further imaging is needed. 1, 3
Critical Exceptions That Would Change Management
If the mass were ≥4 cm: Even radiologically benign masses of 4 cm or larger require repeat imaging in 6-12 months due to higher baseline malignancy risk (21.1% for masses ≥40 mm). 1, 2 However, at 2.6 cm, this does not apply.
If growth >5 mm/year detected: Any adrenal nodule growing more than 5 mm annually requires adrenalectomy consideration after repeating functional workup, regardless of initial benign appearance. 1, 3 The documented stability excludes this concern.
If new hormonal symptoms develop: Annual symptom screening is reasonable even without scheduled imaging, as 17% of initially non-functional masses develop hormone secretion after 1 year, increasing to 47% by 5 years. 1 However, routine annual biochemical testing is not mandated by the most recent guidelines for masses <4 cm that are radiologically benign. 1
Management of the 5 mm Left Lower Lobe Nodule
The incidental 5 mm pulmonary nodule requires separate evaluation according to Fleischner Society guidelines, which is outside the scope of adrenal mass management but typically involves follow-up CT chest based on patient risk factors.
Common Pitfalls to Avoid
Do not perform routine adrenal biopsy: Biopsy is contraindicated for adrenal incidentalomas unless there is known extra-adrenal malignancy and confirmation of metastatic disease would alter management. 1, 2
Do not continue imaging "just to be safe": The evidence shows that benign-appearing masses <4 cm have essentially 0% risk of malignant transformation (0% to <1% in large series), making continued surveillance medically unnecessary and exposing patients to cumulative radiation without benefit. 1
Do not assume bilateral masses indicate metastatic disease: Bilateral adenomas are common, especially in older patients, and each nodule should be characterized independently. 4