Overview
Definition:
An adrenal incidentaloma is an adrenal mass discovered incidentally during imaging performed for unrelated reasons in an adolescent
These masses are common and typically benign, but require evaluation for hormonal hypersecretion and malignancy potential.
Epidemiology:
The prevalence of adrenal incidentalomas in adolescents is not well-defined but is thought to increase with age, similar to adults
Autoimmune conditions and genetic predispositions may play a role
Most are adenomas, with pheochromocytomas and adrenocortical carcinomas being rarer.
Clinical Significance:
Prompt and appropriate hormonal workup is crucial to identify potentially treatable conditions that can lead to significant morbidity and mortality in adolescents, such as subclinical Cushing's syndrome, pheochromocytoma, or primary aldosteronism
Early detection impacts long-term health and development.
Clinical Presentation
Symptoms:
Often asymptomatic
When present, symptoms depend on hormonal hypersecretion: weight gain, striae, moon facies, hypertension (Cushing's syndrome)
Episodic headaches, palpitations, sweating, anxiety (pheochromocytoma)
Hypertension and hypokalemia (primary aldosteronism)
However, many are discovered incidentally.
Signs:
Physical examination may reveal signs of hormonal excess: obesity, hypertension, hirsutism, acne, striae, muscle weakness, hypokalemia (e.g., decreased reflexes)
Sometimes a palpable abdominal mass, though rare.
Diagnostic Criteria:
No specific diagnostic criteria for adrenal incidentaloma itself, as it is an incidental finding
The diagnosis of hormonal hypersecretion is based on biochemical tests and clinical manifestations, following established guidelines for each specific endocrine disorder.
Diagnostic Approach
History Taking:
Detailed history regarding symptoms of hormonal excess: weight changes, fatigue, palpitations, headaches, mood changes, polyuria/polydipsia
Family history of endocrine disorders, hypertension, or adrenal tumors
Medication history (steroids, oral contraceptives).
Physical Examination:
Thorough physical examination focusing on signs of hypercortisolism (central obesity, moon facies, buffalo hump, striae, hirsutism), hypertension, and hypokalemia
Assess for cardiovascular and neurological findings
Measure height and weight for growth assessment.
Investigations:
Initial biochemical screening should include: 1
Urinary free cortisol (UFC) or 24-hour urine for cortisol and 17-ketosteroids
2
Plasma free metanephrines or 24-hour urinary metanephrines and normetanephrines to rule out pheochromocytoma
3
Plasma aldosterone-to-renin ratio (ARR) to screen for primary aldosteronism
If Cushing's is suspected, consider overnight dexamethasone suppression test (DST)
Imaging: CT or MRI of adrenal glands for size, morphology, and characteristics (fat content, calcifications)
Size >4 cm is a relative indication for further evaluation for malignancy.
Differential Diagnosis:
Adrenal adenoma (non-functional), pheochromocytoma, adrenocortical carcinoma, Cushing's syndrome (ACTH-dependent and independent), primary aldosteronism, congenital adrenal hyperplasia (rare presentation), adrenal cysts, adrenal hemorrhage, myelolipoma, metastasis.
Hormonal Workup Details
Cushings Syndrome Screening:
24-hour UFC > 50-100 mcg/day (or > 140-280 nmol/day) or overnight DST with 1 mg dexamethasone showing serum cortisol > 1.8 mcg/dL (or > 50 nmol/L) is suggestive
Confirmatory tests like low-dose DST, CRH stimulation test, or ACTH levels are then performed.
Pheochromocytoma Screening:
Plasma free metanephrines > 2-3 times the upper limit of normal is highly suggestive
24-hour urinary fractionated metanephrines and normetanephrines are also sensitive
Further testing with clonidine suppression test or imaging may be needed.
Primary Aldosteronism Screening:
Plasma aldosterone-to-renin ratio (ARR) > 20-30, with a plasma aldosterone > 10-15 ng/dL (or > 275-415 pmol/L)
Confirmatory tests include saline infusion test or oral sodium loading test.
Androgen Secreting Tumors:
Elevated serum dehydroepiandrosterone sulfate (DHEA-S) and testosterone levels may indicate androgen excess, particularly in the presence of virilization
Further workup for adrenocortical carcinoma or other sources is warranted.
Imaging Evaluation
Ct Scan:
Preferred initial imaging
Assesses size, morphology, attenuation values
Lipid-rich adenomas typically have < 10 Hounsfield Units (HU)
Masses > 20 HU may suggest malignancy or non-adenoma origin.
Mri Scan:
Useful for characterizing indeterminate lesions on CT, especially for assessing T1 and T2 signal intensities and contrast enhancement patterns
Useful for evaluating local invasion.
Size And Growth:
Masses < 2 cm are generally benign
Masses > 4 cm have a higher risk of malignancy
Serial imaging may be considered for smaller, non-functional lesions to monitor growth, typically every 6-12 months for 1-2 years.
Management Strategy
Observation:
For small (< 2 cm), radiologically benign-appearing, and biochemically non-functional incidentalomas
Regular follow-up with clinical assessment and biochemical screening (annually for a few years).
Medical Management:
Treatment of any identified hormonal hypersecretion (e.g., antihypertensives for Cushing's or Conn's syndrome, alpha/beta blockers for pheochromocytoma).
Surgical Management:
Adrenalectomy is indicated for functional tumors (hormone-secreting), suspected malignancy (lesions > 4-5 cm, rapid growth, suspicious imaging features), or symptomatic lesions
Laparoscopic adrenalectomy is the preferred approach.
Follow Up And Prognosis
Follow Up Protocol:
For observed incidentalomas, follow-up includes reassessment of hormonal status and imaging
Frequency and duration depend on initial findings, size, and growth
For post-adrenalectomy patients, long-term endocrine monitoring and follow-up for recurrence are essential.
Factors Affecting Prognosis:
Prognosis is generally excellent for benign, non-functional adrenal adenomas
For functional tumors, prognosis depends on the specific hormonal excess and its control
Malignant tumors (adrenocortical carcinoma) have a poorer prognosis and depend on stage and resectability.
Prognosis In Adolescents:
Early diagnosis and management of functional adrenal incidentalomas in adolescents can significantly improve long-term outcomes and prevent complications like growth retardation, severe hypertension, or cardiovascular disease, leading to a normal life expectancy.
Key Points
Exam Focus:
The hormonal screening tests for Cushing's syndrome, pheochromocytoma, and primary aldosteronism are high-yield
Understanding the imaging characteristics (HU on CT, signal intensity on MRI) and size criteria for malignancy risk is crucial.
Clinical Pearls:
Always consider adrenal incidentalomas in adolescents with unexplained hypertension or electrolyte abnormalities
A systematic approach to hormonal workup is key
Never forget pheochromocytoma in patients with palpitations and hypertension, even in the absence of classic symptoms.
Common Mistakes:
Overlooking subtle hormonal abnormalities
Inadequate hormonal screening
Misinterpreting imaging findings
Delaying referral for functional or suspicious lesions
Not following up adequately on observed masses.