⚠️ Note: Glucagonomas may be associated with other tumours in Multiple Endocrine Neoplasia type 1 (MEN1), though this is rare (<3% of cases).
📖 About Glucagonoma
- Glucagonoma is a rare pancreatic neuroendocrine tumour arising from α-cells of the islets of Langerhans.
- Often diagnosed at an advanced stage due to subtle early features.
- Most are sporadic, though a minority are linked to MEN1 syndrome.
⚙️ Aetiology
- Slow-growing α-cell tumour producing excessive glucagon → hyperglycaemia & catabolism.
- 80% are malignant at diagnosis.
- Common metastatic sites: liver, lymph nodes, bone, adrenals, kidneys, lungs.
🩺 Clinical Presentation
- Metabolic: Hyperglycaemia, weight loss, diabetes (often mild, non-ketotic).
- Systemic: Glossitis, diarrhoea, anaemia.
- Dermatologic hallmark: Necrolytic Migratory Erythema 🩹 - painful, blistering rash associated with niacin deficiency; often improves with octreotide.
- Thrombosis risk: High rates of DVT/PE due to increased coagulation factors.
🔎 Investigations
- Bloods: FBC, U&E, LFTs, CRP, glucose.
- Hormonal marker: Elevated plasma glucagon.
- Imaging: CT/MRI abdomen → ~50% metastatic at diagnosis.
- Gold standard: Selective visceral angiography (sensitive for primary tumour & liver mets).
- Advanced: Pancreatic venous sampling for glucagon (useful in small/occult lesions).
💊 Management
- Symptomatic control:
- Octreotide (somatostatin analogue) → suppresses glucagon secretion & improves rash.
- Niacin supplementation if deficiency confirmed.
- Definitive: Surgical resection = treatment of choice if localized.
- Diabetes management: Often controlled with low-dose insulin (non-ketotic, relatively mild).
- Advanced disease: Debulking surgery, embolisation, or targeted systemic therapies (everolimus, sunitinib, PRRT).
🚨 Clinical Pearls
🔑 Think glucagonoma in weight loss + diabetes + rash (NME).
🧪 Glucagon >500 pg/mL is strongly suggestive.
🩸 Watch for VTE – common and sometimes presenting feature.
🧬 Screen for MEN1 (parathyroid, pituitary, pancreatic tumours) if family history or multiple tumours.
📚 References
