CONDITIONS · NEUROENDOCRINE HEALTH
Neuroendocrine
Tumours (NETs)
A diverse group of rare tumours that arise from the body's hormone-producing cells. They often grow slowly and can be very treatable — but because their symptoms are subtle and varied, expert assessment and coordinated care are essential. Specialist endocrine input from consultant Dr Sheharyar Qureshi.

At a glance
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Arise from neuroendocrine cells found throughout the body
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Most commonly occur in the digestive system and lungs
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Often slow-growing, and frequently very treatable
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Best managed through specialist, multidisciplinary care
01 — UNDERSTANDING THE CONDITION
What are neuroendocrine tumours?
Neuroendocrine tumours are a varied group of tumours that develop from neuroendocrine cells — specialised cells that are found throughout the body and share features of both nerve and hormone-producing cells. These cells help regulate many bodily processes by releasing hormones into the bloodstream. Because they are so widely distributed, NETs can arise in many different organs, most commonly in the digestive system (the stomach, bowel and pancreas) and the lungs.
NETs vary enormously. Some are "functioning" — meaning they release excess hormones that cause distinctive symptoms — while others are "non-functioning" and may cause no hormonal symptoms at all, coming to light only when they grow large enough to be noticed or are found incidentally on a scan. Many NETs grow slowly over long periods, though a minority behave more actively.
This diversity is why NETs are best assessed by specialists. An endocrinologist plays an important role in the team — particularly in identifying and managing the hormonal effects of functioning tumours, and in coordinating the wider assessment needed to understand each individual tumour.
02 — SIGNS & SYMPTOMS
How NETs can present
Symptoms depend heavily on whether a tumour produces excess hormones, and on where it is located. Many symptoms are non-specific and can mimic far more common conditions — one reason NETs can take time to diagnose.
Hormone-related
The pattern of symptoms depends on which hormone is being overproduced.
Functioning tumours
When a tumour releases excess hormones
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Flushing of the skin and diarrhoea (carcinoid syndrome)
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Episodes of low blood sugar, sweating and confusion
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Recurrent stomach ulcers and reflux
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Wheezing or a rapid heartbeat during episodes
Local or non-specific
These are often found incidentally, or cause symptoms only as they grow.
Non-functioning tumours
When a tumour produces no excess hormone
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Vague abdominal discomfort or bloating
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A change in bowel habit
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Unexplained tiredness or weight change
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Often discovered on a scan done for another reason
03 — THE TYPES WE HELP ASSESS
Types of neuroendocrine tumour
NETs are grouped by where they arise and whether they produce excess hormones. These are some of the more commonly encountered types.
Gastrointestinal NETs
Stomach, bowel & more
The most common site for NETs. Often slow-growing, historically referred to in some cases as "carcinoid" tumours.
Pancreatic NETs
Arising in the pancreas
NETs of the pancreas, which may be functioning or non-functioning. This group includes insulinoma and gastrinoma.
Lung NETs
Bronchial tumours
NETs arising in the lungs, spanning a range from slow-growing to more active forms, assessed alongside respiratory specialists.
Insulinoma
Excess insulin
A usually benign pancreatic NET producing excess insulin, causing episodes of low blood sugar (hypoglycaemia).
Gastrinoma
Excess gastrin
A NET producing excess gastrin, leading to high stomach acid and recurrent ulcers (Zollinger–Ellison syndrome).
Functioning & non-functioning
A key distinction
Whether a tumour releases excess hormones shapes its symptoms and its management — a central question in every assessment.
04 — DIAGNOSIS
How NETs are diagnosed
Diagnosing a NET usually involves several complementary tests — measuring hormones and markers in the blood or urine, specialised imaging, and confirming the diagnosis with a tissue sample. The endocrine element focuses on the hormonal picture.
Detailed consultation
A careful review of your symptoms and their pattern over time, your medical and family history, and a clinical examination.
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