Ans. B. Mesenteric carcinoid tumora. Carcinoid tumors of the small intestine are regarded as low-grade malignant neoplasms. Almost 90 per cent of them are located distally and they may be multiple in approximately one-third of cases.b. Carcinoid arises within the basal portion of the mucosa and often extends into the submucosa, infiltrating the intestinal wall and serosa.c. Less frequently intraluminal growth results in a polypoid lesion. Invasion of the muscular layers of the intestinal wall may lead to fibrosis of the surrounding submucosa, the mesentery and mesenteric vesselsd. The primary tumor rarely produces symptoms, largely because of its small size and its deep mucosal location. Abdominal pain, diarrhoea or an abdominal mass may be encountered, but gastrointestinal hemorrhage is extremely rare. The carcinoid syndrome is seen in one-third of jejunoileal carcinoids that have metastasized to the liver.e. The radiological features of carcinoid tumor are nonspecific and reflect the stage of evolution of the pathological process at the time of examination. They may be those of: (A) the primary lesion, appearing as solitary or multiple, round, smoothly outlined intraluminal filling defects; (B) those of a secondary mesenteric mass, causing stretching, rigidity and fixation of ileal loops; (C) those due to interference with the ileal blood supply, resulting in thickening of valvulae conniventes and chronic ischaemic intestinal changes; or (D) those of fibrosis associated with tumor spread, presenting as sharp angulation of a loop or a stellate, spoke-like arrangement of adjacent loopsf. Carcinoid tumors are best recognized on CT on the basis of mesenteric findings. Secondary mesenteric changes include a discrete, unifocal, soft tissue mass, usually associated with linear strands radiating into surrounding fat, while displacing adjacent intestinal loops.g. Hyper vascular liver metastases, usually hypodense on unenhanced images, mesenteric lymphadenopathy and dystrophic calcification in metastatic nodes, liver metastases or in the mesenteric mass may be also encountered