Neuroendocrine tumors (NETs), sometimes referred as a carcinoids, are abnormal growths that begin in the neuroendocrine cells, which are distributed widely throughout the whole body. While some features of Neuroendocrine tumors are unique to the site of origin, other characteristics are shared, regardless.

Different types of NETs cause different symptoms, depending on the location of the tumor, and whether the NET is functional or nonfunctional. Functioning NETs are defined based upon the presence of clinical symptoms due to excess hormone secretion by the tumor. Nonfunctional NETs do not secrete hormones. They may produce symptoms caused by the tumor's growth.

Characteristics of neuroendocrine tumors:

• Flushing (redness, warmth) in the face or neck without sweating

• Diarrhea, including at nighttime

• Shortness of breath, rapid heartbeat/palpitations

• High blood pressure

• Fatigue, weakness

• Abdominal pain, cramping, feeling of fullness

• Unexplained weight gain or loss

• Wheezing, coughing

• Swelling in the feet and ankles

• Skin lesions, discolored patches of skin, thin skin

• High blood glucose levels (frequent urination, increased thirst, increased hunger)

• Low blood glucose levels (shakiness, dizziness, sweating, fainting)