Phaeochromocytoma Flashcards
Phaeochromocytoma refers to a …-secreting tumour of chromaffin cells.
Phaeochromocytoma refers to a catecholamine-secreting tumour of chromaffin cells.
Chromaffin cells are predominantly found in the …, but also in the sympathetic paravertebral ganglia of the thorax, abdomen, and pelvis.
Chromaffin cells are predominantly found in the adrenal medulla, but also in the sympathetic paravertebral ganglia of the thorax, abdomen, and pelvis.
Catecholamine-secreting tumours may arise from the adrenal medulla or from the sympathetic ganglia and are known as phaeochromocytomas and paragangliomas respectively:
Phaechromocytoma: arising from the adrenal medulla, accounts for 80-85% of such tumours.
Catecholamine-secreting paraganglioma: arising from the sympathetic ganglia, accounts for 15-20% of such tumours. Sometimes referred to as ‘extra-adrenal phaeochromocytomas’.
Paragangliomas
Paragangliomas may arise from both parasympathetic and sympathetic ganglia. Paragangliomas affecting parasympathetic ganglia are commonly referred to as head and neck paragangliomas. They are usually non-secretory, derived from non-chromaffin cells and named after the tumour location (e.g. carotid body, glomus tympanicum, glomus jugulare).
Phaeochromocytomas and paragangliomas are … tumours.
Phaeochromocytomas and paragangliomas are rare tumours.
Phaeochromocytomas account for < …% of patients with hypertension. They most commonly present in the 4th or 5th decade, but at a younger age in hereditary cases. Around 10% of cases occur in children.
The majority of tumours are sporadic, but up to 40% have a hereditary component.
Phaeochromocytomas account for < 0.2% of patients with hypertension. They most commonly present in the 4th or 5th decade, but at a younger age in hereditary cases. Around 10% of cases occur in children.
The majority of tumours are sporadic, but up to 40% have a hereditary component.
Patients with … phaechromocytoma are more likely to be older and present with classic features. This is because screening for phaeochromocytoma is more well established in hereditary cases. Several susceptibility genes have been identified in phaeochromocytoma. As such, genetic testing should be considered in all patients, usually following resection.
Patients with sporadic phaechromocytoma are more likely to be older and present with classic features. This is because screening for phaeochromocytoma is more well established in hereditary cases. Several susceptibility genes have been identified in phaeochromocytoma. As such, genetic testing should be considered in all patients, usually following resection.
Up to 40% of phaeochromocytomas may have a hereditary component. Three familial syndromes are strongly associated with these catecholamine-secreting tumours:
Multiple endocrine neoplasia (MEN) type 2: autosomal dominant disorder due to a RET proto-oncogene mutation characterised by medullary thyroid cancer, phaechromocytoma and primary hyperparathyroidism. Phaechromocytoma is seen in 50% of cases. See our MEN syndromes notes for more details.
Von Hippel-Lindau (VHL) syndrome: autosomal dominant disorder due to VHL genetic mutation. Characterised by multiple tumours types including phaeochromocytoma, paraganglioma, hemangioblastoma (often involving cerebellum), renal cell carcinoma and many others. Phaeochromocytoma is seen in 10-20% of cases and frequently bilateral.
Neurofibromatosis (NF) type 1: autosomal dominant disorder due to a mutation in the NF1 gene. Characterised by multiple neurofibromas, cafe au lait spots, axillary and inguinal freckling, central nervous system gliomas and phaeochromocytomas in around 3% of cases.
Phaeochromocytomas are neuroendocrine tumours arising from … cells.
Phaeochromocytomas are neuroendocrine tumours arising from chromaffin cells.
The clinical manifestations of phaeochromocytomas are due to excess secretion of catecholamines from tumours leading to either paroxysmal or continuous symptoms. Catecholamines have wide-ranging effects as part of the normal sympathetic nervous system through activation of alpha and beta-adrenergic receptors. These effects include:
Alpha-adrenergic: elevated bloods pressure, increased cardiac contractility, increased glucose utilisation (glycogenolysis/gluconeogenesis).
Beta-adrenergic: increased heart rate, increased cardiac contractility.
Precipitants of hypertensive crisis
Drugs: opiates, dopamine antagonists, beta-blockers, cocaine, tricyclic antidepressants
Physical: direct pressure or handling during surgery
Anaesthesia: endotracheal intubation
Tumour characteristics
There are some key characteristics about phaeochromocytomas and paragangliomas.
Locations: >95% are located within the abdomen with up to 90% of these are intra-adrenal (i.e. phaeochromocytomas)
Laterality: multiple tumours are seen in 5-10% of cases and hereditary cases are more likely to be bilateral
Malignant potential: ~10% of cases are malignant. Malignant spread may occur a long-time following resection.
Phaeochromocytomas are characterised by a triad of…
Phaeochromocytomas are characterised by a triad of episodic headache, sweating and tachycardia.
Classically, clinical features of phaeochromocytoma are ….
Classically, clinical features of phaeochromocytoma are paroxysmal. However, some patients may have more persistent symptoms, while others are asymptomatic. Important to remember that even patients with essential hypertension may have paroxysmal symptoms.
Symptoms of phaeochromocytoma
Asymptomatic (50%): may be found incidentally on imaging or at autopsy Headache (90% in symptomatic): variable in duration and intensity Sweating (60-70% in symptomatic) Tachycardia Palpitations Dyspnoea Weakness Tremor Nausea
Suspected phaeochromocytoma - tests
