Carcinoid tumor of the small intestine: MDCT findings with pathologic correlation.
BACKGROUND
MDCT currently frequently represents the first choice modality for imaging in acute or subacute abdominal conditions implicating the small bowel. As a consequence, the MDCT features of intestinal carcinoid tumors and of their peculiar metastatic spread have to be known by abdominal radiologists.


METHODS
These features are described and illustrated in the retrospective review of seven proven cases of small intestine carcinoids diagnosed and treated in our institution. The findings are described and correlated with gross anatomy specimens.


RESULTS
The primary tumour clearly appeared as a contrast-enhancing intraluminal lesion in all cases except in one case in which the primary lesion remained unlocalized and in another in which the primary tumour finally appeared infracted at gross anatomy. The maximal tumoral enhancement was obtained in 3 patients imaged during the acute arterial phase. The diameter of the primary tumour ranged from 1 to 3 cm and all masses were ileal comprising one lesion in the proximal ileum, two in the medium ileum and three in the distal ileum. 6/7 patients had multiple prominent mesenteric nodal metastases, all also appearing as hypervascularised enhancing masses. In 4/7 patients the nodal metastases represented the major finding being much prominent and larger than the primary tumour. Signs of retractile mesenteritis with soft tissue stranding, retraction and stellate pattern of the mesentery were found around the mesenteric metastases in 5/7 patients and direct incarceration of vessels were found in 3 cases.


CONCLUSIONS
The analysis of the arterial phase of MDCT study appears primordial to detect the sometimes very small but intensively enhancing primary tumor and to delineate encasement or direct obstruction of mesenteric vessels frequently caused by enhancing nodal metastases which volume often exceeds that of the primary tumor. Secondary retractile mesenteritis, deformation or ischemia of bowel loops, and hypervascular hepatic metastases are typical associated findings.
Coulier
B
B
Department of Diagnostic Radiology, Clinique St Luc, Bouge 5004 (Namur), Belgium. bcoulier@skynet.be
Pringot
J
J
Gielen
I
I
Maldague
P
P
Broze
B
B
Ramboux
A
A
Clausse
M
M
D000368:Aged; D000369:Aged, 80 and over; D002276:Carcinoid Tumor / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D003287:Contrast Media / Q000008:administration & dosage; D003974:Diatrizoate Meglumine / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007414:Intestinal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D007421:Intestine, Small; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*
D003287:Contrast Media; D003974:Diatrizoate Meglumine