CT evaluation of small bowel carcinoid tumors

Transcription

1 CT evaluation of small bowel carcinoid tumors Poster No.: C-0060 Congress: ECR 2015 Type: Educational Exhibit Authors: N. V. V. P. Costa, L. Nascimento, T. Bilhim ; Estoril/PT, PT, Lisbon/PT Keywords: Abdomen, Gastrointestinal tract, Small bowel, CT, Contrast agentoral, Contrast agent-intravenous, Diagnostic procedure, Neoplasia, Metastases, Obstruction / Occlusion DOI: /ecr2015/C-0060 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 11

2 Learning objectives To review, describe and illustrate the spectrum of imaging findings of small bowel carcinoid tumors (SBCT) using abdominal computed tomography (CT) scan. Elucidate the most common appearances of SBCT liver metastases on CT images. Background SBCT are rare neuroendocrine neoplasms that constitute nearly 2% of all gastrointestinal tumors. Approximately 85% of carcinoid tumors arise in the gastrointestinal tract. They are the most common primary small bowel cancer. Since it's a slow growing tumor, most are small (few centimeters) when detected and they can be difficult to be seen in routine CT scans and even at surgery. In 40 to 80% of the cases there can be a secondary mesenteric involvement. Although we cannot always see the primary tumor in the small bowel wall, CT is still a very important technique to show the mesenteric extension of the tumors, to detect the liver metastasis and to guide the percutaneous biopsy if indicated. Except in carcinoid syndrome (10%), the symptoms are usually vague and the diagnosis is delayed until the imaging procedures. The sensitivity of CT scan is reported to be around 80%. Findings and procedure details In case of clinical suspicion of SBCT we perform multidetector CT with multiplanar reconstructions using oral and i.v. (120 ml injected at 2-3 ml/sec) nonionic iodinated contrast. We acquire dual-phase images during arterial and venous times. We reviewed retrospectively all the 21 cases of SBCT with available CT scans at our institution during the period of April 2011 to April CT scans were evaluated for size, margins, density, small bowel wall thickening, radiating strands, calcifications, mesenteric vessels and local lymph-nodes size. The patients study were 15 men and 6 women, ranging in age from 44 to 94 years old with median age of 68 years. Page 2 of 11

3 SBCT can manifest as an intraluminal lesion (figure 1 and 2) or as a mural mass with mesenteric extension (figure 3). In the later, the tumor presents as a spiculated mesenteric solid mass, calcified in the center, with contiguous thickening of small bowel loops (figure 4). In 19 of the 21 cases, we could see a thickened small bowel wall surrounding the mesenteric masses (figure 5). Calcification was seen in 17 of the cases and most of them were classified as coarse calcifications (figure 4 and 6). There were 12 mesenteric masses and sizes ranged from 1 to 5 cm (median 2.9 cm). Most had well defined borders and the margins were easily outlined. In only 4 cases the margins were difficult to outline because of the radiating strands overlap. All the masses showed soft tissue strands radiating from the mesenteric masses to the adjacent small bowel walls. Radiating strands ("spoke-wheel" pattern) around the tumor represent the desmoplastic reaction and mesenteric fibrosis (figure 3, 5 and 6). It's common to find engorgement of the local mesenteric vessels and lymph-nodes (figure 3 and 5). The liver metastases of SBCT have a characteristic CT appearance because of their vascularity pattern. The arterial time acquisition is essential because on early phase imaging after the administration of the IV contrast agent, the metastases enhance brightly. During venous time scan, this lesions can become isodense with the liver parenchyma and pass unnoticed (figure 7). The differential diagnosis should include the rectractile mesenteritis and treated lymphoma since they can have a very similar appearance. Images for this section: Page 3 of 11

4 Fig. 1: Intraluminal component of carcinoid with a circumferential solid mass in one proximal ileum loop (red arrow). Page 4 of 11

5 Fig. 2: Duodenal carcinoid with intraluminal small solid mass (red line). No mesenteric extension nor metastases. Page 5 of 11

6 Fig. 3: Mural mass thickening in small bowel loop (red line) with mesenteric extension demonstrated by the presence of a mesenteric mass (blue line) with adjacent desmoplastic reaction (white arrows) and multiple local enlarged lymph-nodes (green lines). Page 6 of 11

7 Fig. 4: Obstructive small bowel ileus because of an ileal carcinoid tumor with localized small bowel wall thickening and mesenteric extension (blue line). Page 7 of 11

8 Fig. 5: Small bowel carcinoid (red line) with obstructive small bowel ileus (blue arrow). Radiating linear strands (white arrows) around the soft tissue mass due to fibrosis (spokewheel pattern). Page 8 of 11

9 Fig. 6: Small bowel carcinoid with wall thickening and mesenteric extension (blue line). Dense and coarse calcification in the center of the mass (red arrow). Page 9 of 11

10 Fig. 7: Dual-phase abdominal CT scan (A and B - arterial phase; C and D - venous phase) in a patient with liver metastases from a duodenal carcinoid. The brightly arterial enhancement metastases (A and B) become isodense to the liver during venous phase (C and D). Page 10 of 11

11 Conclusion CT is an excellent technique to show the location of the primary tumor, the involvement of the mesentery, the enlargement of the retroperitoneal lymph-nodes and the distant metastases (liver). Personal information References Levy, Andela D et al. Gastrointestinal Carcinoids: Imaging Clinicopathologic Comparison. RadioGraphics 2007; 27: Features with Horton, Karen et al. Carcinoid tumors of the small bowel: a multitechnique imaging approach. AJR 2004;182: Vinik AI, et al. Clinical features, diagnosis and localization of carcinoid tumors and their management. Gastroenterol Clin North Am 1989;18: Bader TR, et al. MRI of carcinoid tumors: spectrum of appearances in the gastrointestinal tract and liver. J Magn Reson Imaging 2001;14: Picus D, et al. Computed tomography of abdominal carcinoid tumors. AJR 1984;143: Buckley JA, et al. Small bowel cancer: imaging features and staging. Radiol Clin North Am 1997;35: Seigel RS, et al. Computed tomography and angiography in ileal carcinoid tumor and retractile mesenteritis. Radiology 1980;134: Bressler EL, et al. Hypervascular hepatic metastases: CT evaluation. Radiology 1987;162:49-51 Dromain C, et al. MR imaging of hepatic metastases caused by neuroendocrine tumors: comparing four techniques. AJR 2003;180: Pantongrag-Brown L, et al. Calcification and fibrosis in mesenteric carcinoid tumor: CT findings and pathologic correlation. AJR Am J Roentgenol 1995; 164(2): Page 11 of 11