Small bowel carcinoid with liver metastases
6 month history of abdominal pain, diarrhea and weight loss with right iliac fossa tenderness. MRI small bowel to look for inflammatory bowel disease.
MRI small bowel (enterography)
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There is an avidly enhancing ovoid shaped lesion in the small bowel mesentery in the right iliac fossa measuring 5 cm in length. A number of similarly enhancing lymph nodes are noted more proximally along the draining vascular pedicle. There is indrawing of distal small bowel loops around the lesion. Mural thickening, edema and hyperenhancement of these small bowel loops is present. The proximal small bowel loops and the large bowel appear normal. On the post-contrast imaging, some target-shaped liver lesions can be appreciated but the diffusion weighted series confirms the presence of innumerable restricted lesions within the liver, as well as markedly restricted diffusion of the mesenteric mass.
Overall, the appearances are highly suggestive of a small bowel mesenteric carcinoid lesion with multiple liver metastases. The small bowel appearances are likely secondary to congestion and a degree of ischemia secondary to vascular compression by the mesenteric mass.
Carcinoid tumors are "cicatrising" - they induce a fibrotic reaction in the mesentery and cause indrawing and tethering of adjacent small bowel loops. They can also compromise the vascular supply and drainage, causing ischemia. Once the tumors metastasize to the liver, patients are prone to carcinoid syndrome as the liver no longer acts as a filter for the secreted hormones.