Adrenal Masses Incidentalomas

💡 Adrenal masses (also called adrenal incidentalomas) are adrenal lesions discovered incidentally on imaging for unrelated reasons. They are seen in up to 5% of CT/MRI scans and represent a wide spectrum from benign, non-functioning adenomas to hormonally active or malignant tumours.

📘 About

• Incidentally detected adrenal lesions occur in 1–5% of abdominal CT or MRI scans.
• Most are benign, non-functioning adenomas, but a small proportion represent malignancy or functional endocrine tumours.
• Accurate assessment is crucial — both for ruling out hormonal excess and for identifying adrenocortical carcinoma or metastasis.

🧬 Genetic and Syndromic Associations

• MEN type 1 and 2
• Carney complex
• McCune–Albright syndrome
• Familial pheochromocytoma–paraganglioma syndromes

🧫 Aetiology

• Infective: Tuberculosis or fungal infection
• Malignant: Adrenocortical carcinoma or metastases (e.g. lung, breast, kidney)
• Inflammatory: Abscess
• Benign: Adrenal adenoma, myelolipoma, haemorrhage
• Endocrine: Phaeochromocytoma, aldosteronoma, Cushing’s adenoma

🩺 Clinical Features (depend on hormone secretion)

• 📍 Abdominal or flank pain/fullness (mass effect)
• 🌕 Glucocorticoid excess (Cushing’s syndrome): central obesity, moon facies, striae, hypertension, diabetes, proximal myopathy, menstrual irregularities
• ⚡ Mineralocorticoid excess (Conn’s syndrome): hypokalaemia, muscle weakness, nocturia, hypertension, oedema
• 💈 Androgen excess: hirsutism, acne, menstrual irregularities, infertility
• 💓 Catecholamine excess (Phaeochromocytoma): episodic headache, palpitations, sweating, pallor, paroxysmal hypertension

🧪 Investigations

• 🧫 Electrolytes: hypokalaemia may suggest hyperaldosteronism.
• 💉 Hormonal work-up:
  • Cortisol: overnight dexamethasone suppression test.
  • Renin–aldosterone ratio: for primary aldosteronism.
  • Urinary catecholamines or plasma metanephrines: for phaeochromocytoma.
  • Androgen profile: testosterone, DHEA-S, androstenedione, LH/FSH, prolactin.
  • 24-hour urinary 17-ketosteroids (17-KS): for adrenocortical carcinoma.
• 🖥️ Imaging:
  • CT/MRI abdomen: define size, density, and morphology.
  • Adrenal adenomas: low attenuation (<10 HU) on unenhanced CT.
  • Phaeochromocytomas: T2 hyperintense.
  • Adrenocortical carcinomas: irregular, necrotic, calcified, >4 cm, often T2 hyperintense.

⚙️ Management Approach

• 🔍 Step 1 – Rule out malignancy: assess tumour size, radiological appearance, and local invasion.
• 🧪 Step 2 – Rule out hormonal activity: exclude cortisol, aldosterone, androgen, and catecholamine excess.
• 🏥 Step 3 – Consider surgery if:
  • Functional tumour (any hormone excess)
  • Non-functioning lesion >4 cm
  • Progressive enlargement on serial imaging
  • Suspicious imaging features (irregular, necrotic, calcified)
  • Phaeochromocytoma confirmed biochemically
• 💊 Not indicated: bilateral hyperplasia with hyperaldosteronism (medical management preferred).
• 🧬 Adrenocortical carcinoma: poor prognosis; median survival 14–36 months even post-resection. Micrometastases are common at diagnosis.

💡 Prognostic Indicators

• Tumour size >6 cm or irregular margins strongly suggest malignancy.
• Non-functioning adenomas <4 cm are usually benign and stable.
• Functional tumours often resolve symptomatically after surgical excision.

📚 References

• Fassnacht M, Arlt W et al. Management of adrenal incidentalomas: European Society of Endocrinology Clinical Practice Guidelines. Eur J Endocrinol. 2016;175(2):G1–G34.
• Young WF. The incidentally discovered adrenal mass. N Engl J Med. 2007;356:601–610.

🧠 Teaching tip: Adrenal incidentalomas are common but potentially serious. Always assess for hormonal excess and malignant features — function and form determine management. Benign, non-functioning lesions <4 cm typically need only periodic imaging.