Multimodality Imaging Findings in Carcinoid Tumors: A Head-to-Toe Spectrum

Abstract

Carcinoid tumors are a rare biologically heterogeneous group of neuroendocrine tumors with a spectrum ranging from benign indolent to aggressive metastatic tumors. They belong to the category of amine precursor uptake and decarboxylase tumors, or apudomas. The most common sites for primary locations are the gastrointestinal and respiratory tracts; however, any organ can be involved. The clinical presentation depends on location, aggressiveness, production of biologically active amines and peptides, paraneoplastic syndromes, and tendency for metastasis. Their reported age-adjusted incidence has increased in recent years, partly due to improved detection at radiologic imaging and endoscopy. Not a ll neuroendocrine cell tumors are carcinoids. Numerous systems have been proposed regarding their nomenclature and classification. Cross-sectional and functional imaging plays an important role in diagnosis, lesion characterization, and staging. Awareness of nomenclature, classification, common sites of involvement, and imaging presentation are pivotal for making the diagnosis. Knowledge of the diverse clinical, pathologic, and radiologic spectrum of carcinoid tumors involving various organs of the body is important for diagnosis and patient management. RSNA, 2017.

MRI of Tumors and Tumor Mimics in the Female Pelvis: Anatomic Pelvic Space–based Approach

“…neuroendocrine tumors, also known as carcinoid tumors, are most frequent in the small intestine, particularly the distal ileum, followed by the colorectum (28). Detection of these tumors is on the rise, possibly owing to the increase in use of endoscopic and imaging studies.…”

“…The primary tumor may be seen at MRI as a small, intermediate T2 SI, avidly enhancing mass or eccentric wall thickening. The associated mesenteric masses show avid enhancement and spiculated margins due to desmoplastic reaction (dense fibrosis around the tumor) with or without tethering and/or retraction of adjacent small bowel loops (28). Calcifications are not readily detected at MRI but are present in up to 70% of cases at CT.…”

Current Applications for Nuclear Medicine Imaging in Pulmonary Disease

“…Pulmonary carcinoid (PC) accounts for more than 25% of all carcinoid tumors in the body and 1–2% of all pulmonary neoplasms [ 74 ]. They have somatostatin receptors (SSTR) and can be identified on somatostatin analog octreotide scans radiolabeled with indium ( 111 In) [ 75 ]. Carcinoid tumors with malignant potential show increased FDG uptake on PET/CT due to high metabolic activity.…”

<p>Clinical Evaluation of Everolimus in the Treatment of Neuroendocrine Tumors of the Lung: Patient Selection and Special Considerations. A Systematic and Critical Review of the Literature</p>

“… 14 These nuclear medicine techniques play an important role in the staging, 15 , 16 detection of recurrence, 17 prediction of the response to PRRT, 18 prediction of positive prognosis, 19 therefore lead to a better clinical management. 20 , 21…”