SBA GI

A. Desmoid tumors are locally invasive forms of fibromatosis, which appear as soft-tissue masses in the mesentery. The margins may appear irregular, but because of its benignity, liver metastases do not occur.
B. Lymphomas result in bowel wall thickening and lymph node masses in the mesentery supplying the involved segment. The marked desmoplastic reaction seen above is not characteristic.
C. Correct. Carcinoid is the most common primary small bowel neoplasm and arises from neuroendocrine cells accounting for the neuroendocrine symptoms. The primary tumor is often too small to be seen by CT. The metastatic mesenteric lymph node mass seen has spiculation and adjacent fibrotic reaction. Systemic symptoms are produced by metastatic disease in the liver synthesizing vasoactive amines that induce the carcinoid syndrome.
D. Primary small bowel adenocarcinoma is rare. Findings include focal wall thickening, narrowing of the lumen, and proximal dilatation.