Abstract: Introduction and aim of the study Irritable bowel syndrome (IBS) and carcinoid syndrome are distinct conditions, functional and neoplastic respectively, yet they often present with similar gastrointestinal symptoms such as diarrhea, bloating and abdominal pain. This clinical overlap can lead to misdiagnosis and delayed identification of neuroendocrine tumors (NETs). This study compares IBS and carcinoid syndrome in terms of pathophysiology, clinical presentation, diagnostic approaches and therapeutic strategies. Emphasis is placed on diagnostic errors and the importance of timely recognition of NETs. Materials and methods A literature review was conducted focusing on diagnostic criteria such as Rome IV, biochemical markers including 5-HIAA and chromogranin A, and imaging modalities like CT, MRI and PET. Publications from 2009 to 2025 were analyzed, with the majority from 2020 to 2024. A total of 24 original research articles were included. ResultsAlthough both conditions share gastrointestinal complaints, features such as facial flushing, valvular heart disease and failure to improve with dietary changes are more suggestive of carcinoid syndrome. IBS is diagnosed based on symptoms alone, while NETs require biochemical and radiological confirmation. ConclusionsAccurate differentiation between IBS and NETs is essential. In patients with persistent, atypical or treatment-resistant symptoms, appropriate testing significantly improves prognosis and may be life-saving. Increased clinical awareness can reduce diagnostic delay and enhance patient outcomes. Keywords: Irritable Bowel Syndrome; Carcinoid Tumor; Neuroendocrine Tumors; Differential Diagnosis; Gastrointestinal Diseases;
Trela et al. (Tue,) studied this question.