Imaging of carcinoid tumors: spectrum of findings with pathologic and clinical correlation

Carcinoid tumors are primary malignant neoplasms that arise from neuroendocrine cells. These cells are located throughout the body, resulting in many possible locations for the development of carcinoid tumor. The most common primary location is the gastrointestinal tract, followed by respiratory and thymic carcinoids. The presentations of these tumors are variable depending on their location, aggressiveness, production of functional peptides, and tendency to invade or metastasize. Carcinoid tumors can be imaged by various modalities including gastrointestinal studies, ultrasound, computed tomography, and magnetic resonance imaging as well as nuclear medicine studies (radioactive octreotide). In this review, we illustrate the spectrum of imaging features of carcinoid tumors in various locations of the human body.