Pitfalls in the diagnosis of carcinoid syndrome

Background. Carcinoid syndrome (CS ) is a rare syndrome, most commonly associated with neuroendocrine neoplasms (NEN s) of the small intestine. Carcinoid syndrome consists of diarrhea, vomiting, abdominal pain, cutaneous flushing, teleangiectasias, bronchoconstriction and increased perspiration. Diagnosis of carcinoid syndrome remains a challenge and it is often delayed.

Objectives. The aim of this study was to characterize patients with CS and define the most sensitive, primary diagnostic tools for CS .

Material and methods. 26 consecutive patients admitted to the Department because of carcinoid-like symptoms. Diagnosis of CS was based on clinical findings and laboratory data (levels of 5-hydroxyindoloacetic acid). Diagnosis of NEN was based on laboratory findings, imaging studies (US , CT , Gallium-68-DOTA TATE PET -CT ) and histopathological analysis. CS due to NEN was diagnosed in 16 subjects (NEN –CS ).

Results. The most common symptoms in non-NEN were increased perspiration, flushes and diarrhea. CgA was elevated (40%; n = 4) in this group. However, elevated levels of 5-HIAA and liver lesions were not presented. In the NEN –CS symptoms were reported more often: flush (93.7%; n = 15), diarrhea (87.5%; n = 14), abdominal pain and teleangiectasis (81.2%; n = 13). Elevated CgA and 5-HIAA were noted in 87.5% (n = 14) and 81.2% (n = 13) respectively. US and CT revealed liver metastases in all patients. The mean duration of symptoms before diagnosis was 28.6 months.

Conclusions. The combination of several symptoms of carcinoid syndrome and liver lesion in easily available abdominal imaging (US and/or CT ) should prompt physicians to quick referral to centres specialized in the diagnosis and treatment of NEN.