What is the initial step in evaluating a pediatric adrenal mass?

Differential Diagnosis and Initial Evaluation of Pediatric Adrenal Mass

Begin with a focused history and physical examination targeting signs of hormone excess, followed immediately by comprehensive hormonal screening and non-contrast CT imaging to characterize the mass, as all pediatric adrenal masses warrant surgical resection given the 30.8% malignancy rate in this population. 1

Differential Diagnosis by Category

Benign Lesions

• Adrenal hematoma (most common, 53.6% of hospitalized children): Typically occurs in neonates or children with abdominal trauma, predominantly male (63.1%), right-sided (71.2%), and <4 cm (73.9%) 2
• Ganglioneuroma: Second most common benign lesion in pediatric series 1
• Adrenocortical adenoma: May be functional or non-functional 1
• Adrenal cyst/pseudocyst: Less common benign finding 1

Malignant Lesions

• Neuroblastoma (36.2% of hospitalized children, most common malignancy): Predominantly male (56.0%), right-sided (66.7%), typically ≥4 cm (85.3%), with frequent metastases at diagnosis 2, 1
• Ganglioneuroblastoma: Less common malignant variant 1
• Adrenocortical carcinoma: Rare but important consideration 3

Initial Evaluation Algorithm

Step 1: Clinical Assessment

Target specific findings during history and physical examination:

• Signs of catecholamine excess: Hypertension, headaches, palpitations, sweating, pallor (pheochromocytoma must be ruled out before any intervention) 3
• Signs of cortisol excess: Weight gain, central obesity, moon facies, buffalo hump, purple striae, easy bruising, proximal muscle weakness 4
• Signs of androgen excess: Virilization, hirsutism, deepening voice, precocious puberty in males 4
• Trauma history: Essential for suspected adrenal hematoma 2
• Age consideration: Benign lesions occur more frequently in older children (mean age 6.5 years vs 1.3 years for malignant lesions) 1

Step 2: Mandatory Hormonal Screening

All pediatric adrenal masses require comprehensive hormonal evaluation before any intervention: 3

• Plasma free metanephrines or 24-hour urinary fractionated metanephrines: Essential to exclude pheochromocytoma before biopsy or surgery (life-threatening hypertensive crisis risk) 3, 5
• 1 mg overnight dexamethasone suppression test: Screen for autonomous cortisol secretion (cortisol >138 nmol/L indicates hypersecretion) 5
• Aldosterone-to-renin ratio: If hypertension or hypokalemia present (ratio >20 ng/dL per ng/mL/hr indicates primary aldosteronism) 5
• Serum androgens (DHEA-S, testosterone, 17-hydroxyprogesterone): If adrenocortical carcinoma suspected or virilization signs present 3, 5
• Plasma methoxytyramine: Provides additional information about malignancy likelihood 3

Step 3: Imaging Characterization

Non-contrast CT is the first-line imaging modality: 3

• Hounsfield Units (HU) measurement: <10 HU indicates benign lesion (0% risk of adrenocortical carcinoma), >20 HU increases malignancy risk to 6.3% 3
• Mass characteristics: Homogeneous, well-circumscribed masses are more likely benign; inhomogeneous appearance with irregular margins suggests malignancy 3
• Size assessment: Masses ≥4 cm have higher malignancy risk (85.3% of neuroblastomas) 2
• CT vs ultrasound: CT shows priority over ultrasound for neuroblastoma diagnosis (P < 0.05), though no significant difference for hematoma detection 2
• Cross-sectional imaging of chest, abdomen, pelvis: Mandatory to detect metastases before surgery 3

MRI serves as complementary imaging and is preferred in pediatric cases to minimize radiation exposure 3, 4

Step 4: Surgical Decision-Making

Critical distinction from adult guidelines: All pediatric incidental adrenal masses should be resected given the 30.8% malignancy rate, regardless of size or imaging characteristics 1

This recommendation differs fundamentally from adult management, where observation is acceptable for small, benign-appearing, non-functional masses. The pediatric data shows no significant difference in size (4.8 cm vs 4.3 cm, P=0.57) or radiologic characteristics between benign and malignant lesions 1.

Common Pitfalls to Avoid

• Never biopsy before excluding pheochromocytoma: This can precipitate a fatal hypertensive crisis 4, 6
• Do not apply adult observation guidelines to pediatric masses: The 30.8% malignancy rate mandates surgical resection 1
• Do not rely solely on size criteria: Malignant and benign lesions show no significant size difference in pediatric populations 1
• Do not skip hormonal evaluation even if mass appears benign radiologically: Functional tumors require specific perioperative management 3
• Do not assume antenatal masses are benign: 2 of 5 antenatally discovered masses were neuroblastoma 1

Multidisciplinary Review Threshold

Obtain immediate multidisciplinary review by pediatric endocrinologists, pediatric surgeons, and radiologists for all pediatric adrenal masses 3

This is particularly critical when imaging is not consistent with a benign lesion, evidence of hormone hypersecretion is confirmed, or when planning surgical intervention 3.