DEAR DR. ROACH: Can you please give more insight into carcinoid syndrome? In particular, I’d like to know its symptoms and how it gets diagnosed and treated? What kind of a doctor would one see with that diagnosis? – S.B.

ANSWER: A carcinoid tumor is a type of neuroendocrine tumor of the digestive tract or lungs. In the gastrointestinal tract, these tumors are now referred to just as neuroendocrine tumors. They can produce substances that in some situations can cause carcinoid syndrome. This usually presents with flushing and diarrhea.

Symptoms are most common with carcinoid tumors of the lung or when the neuroendocrine tumor has spread. The liver normally inactivates these substances, so it is when the disease has spread to the liver that people become symptomatic. The blood from lung carcinoid tumors does not go directly to the liver, which is why lung carcinoid tumors may cause carcinoid syndrome without liver involvement. Still, more than 90% of people with carcinoid syndrome have metastatic disease – cancer that has spread to distant locations.

The diagnosis can be made by a combination of urine tests looking for the commonly produced substances, such as 5-hydroxyindoleacetic acid (5-HIAA), and by anatomic tests such as scans or endoscopy.

In the past, neuroendocrine tumors were considered benign, but a better understanding of these tumors has led them to be classified as cancers and treated aggressively. Oncologists with special expertise in gastrointestinal cancers are the ideal specialists to see for treatment.

Treatment may be surgical – for example, to remove metastatic disease to the liver – or medical, such as octreotide, which inhibits release of the substances which cause flushing and diarrhea, and significantly improves symptoms in 80% or more of people with carcinoid syndrome.

DEAR DR. ROACH: During a hospital stay in which I was admitted for a urinary tract infection and possible sepsis, a CT scan without contrast noted an abdominal nodule that the radiologist said “may represent a reactive prominent lymph node.” In numerous tests – including two upper GI series, an MRI and two additional CT scans with contrast – nothing abnormal appeared. Now my gastroenterologist wants to order an EGD/EUS even though I am hesitant because he is not sure what we are looking for. I have no symptoms and am concerned that this is just another test to waste my money. – D.L.

ANSWER: Incidental findings in modern advanced scanning are routine, and enlarged lymph nodes – a place where immune and inflammatory cells gather – are among the most common of these. Many or most of these will be what the radiologist suspected. The term “reactive” is used to mean the lymph node becomes enlarged, often due to infection. Any serious infection may cause enlargement of the lymph nodes. A very few of these will turn out to be more serious, and we worry most about cancer.

The size, position and, above all, progression of the lymph node help determine whether it is benign (such as a reactive node) or malignant (due to cancer). Given that your gastroenterologist has ordered several tests to further evaluate this with no abnormal findings provides almost complete reassurance that this is nothing to worry about.

A tiny doubt may remain, but further testing may cause more harm than good. EGD, which is an upper endoscopy, has few risks but rarely can cause a perforation in the stomach or intestine. EUS is an endoscopic ultrasound, done at the same time as the EGD. I doubt he is trying to waste money, but you can certainly tell him you are willing to live with the near-certainty that the finding was benign.

Dr. Keith Roach is a syndicated columnist.