What is the management approach for a left adrenal nodule identified on a computed tomography (CT) scan?

From the Guidelines

The management of a left adrenal nodule found on CT scan should prioritize a focused history and physical examination to identify signs/symptoms of adrenal hormone excess, adrenal malignancy, and/or extra-adrenal malignancy, as recommended by the most recent guideline 1. The approach to managing a left adrenal nodule involves several key steps, including:

• Initial assessment of the nodule's size and imaging characteristics to determine if it is likely benign or if further evaluation is needed.
• Biochemical evaluation to rule out functional tumors, including tests for excess cortisol, catecholamines, and aldosterone, as suggested by 1.
• For nodules smaller than 4 cm without suspicious features, follow-up imaging in 6-12 months is appropriate to ensure stability, as recommended by 1.
• Nodules larger than 4 cm or those with concerning radiographic features generally warrant surgical removal due to increased malignancy risk, as indicated by 1.
• If imaging is indeterminate, additional studies like MRI, adrenal protocol CT, or PET scan may help characterize the lesion, and a multidisciplinary review by endocrinologists, surgeons, and radiologists should be considered, as suggested by 1.
• Patients with symptoms suggesting hormonal excess require more urgent evaluation, and the management approach should be individualized based on the patient's clinical presentation and the results of diagnostic tests, as recommended by 1. Key considerations in the management of adrenal nodules include:
• The risk of malignancy, which increases with nodule size and suspicious imaging features.
• The potential for hormonal excess, which can have significant clinical consequences if left untreated.
• The importance of a multidisciplinary approach to management, involving endocrinologists, surgeons, and radiologists, as recommended by 1.
• The need for individualized decision-making, taking into account the patient's clinical presentation, diagnostic test results, and preferences, as suggested by 1.

From the Research

Management Approach for Left Adrenal Nodule on CT Scan

The management approach for a left adrenal nodule identified on a computed tomography (CT) scan involves several steps, including characterization of the nodule and differentiation from other adrenal lesions.

• Characterization of adrenal nodules can be done using unenhanced CT and chemical-shift MRI, which have high specificity for lipid-rich adenomas 2.
• Dual-energy CT can also be used to characterize adrenal nodules, providing comparable sensitivity to chemical-shift MRI for the diagnosis of lipid-rich adenomas 2.
• For lipid-poor adenomas, multiphase adrenal washout CT can be used to differentiate them from metastases, but this method has limitations in diagnosing hypervascular malignancies and pheochromocytoma 2.

Role of CT and MRI in Characterization of Adrenal Lesions

• CT has higher sensitivity for detection of small adrenal tumors and adrenal hyperplasia than MRI 3.
• MRI is an important tool in characterizing adrenal masses that cannot be characterized using unenhanced CT, especially those with attenuation values >10 Hounsfield units 3.
• The choice between CT and MRI depends on the specific characteristics of the adrenal lesion and the clinical context.

Distinguishing Pheochromocytoma from Adrenal Adenoma

• Pheochromocytomas can have a variable spectrum of imaging appearances, making accurate diagnosis challenging 4.
• Cystic appearance within adrenal nodules on contrast-enhanced CT can be used to distinguish pheochromocytoma and malignant adrenal tumors from adenomas, with high specificity but low sensitivity 5.
• Modified CT criteria, including lesion attenuation, enhanced CT values, and intralesional cystic degeneration, can improve diagnostic performance in distinguishing pheochromocytoma from adrenal adenoma 6.