Carcinoid syndrome in the absence of hepatic metastases: correlation of CT and In-111 octreotide imaging

Abstract

A 49-year-old man was hospitalized for investigation of a 2-year history of flushing and diarrhea. His urinary 5-hydroxyindoleacetic acid level was elevated. CT scanning showed no evidence of hepatic metastases and equivocal masses in the mesentery and right pelvis. In-111 octreotide imaging confirmed focal increased uptake in the midabdomen, right iliac fossa, and lower right pelvis at 24 and 48 hours. At laparotomy, soft tissue masses were resected from the mesentery, lower right pelvis, and small bowel in the right iliac fossa. One of the tumor masses was contained within a Meckel’s diverticulum in the terminal ileum. No liver abnormality was found. All resected masses showed classical carcinoid histologic signs. Symptoms resolved immediately after surgery. FIGURE 1Fig. 1: A CT image at the level of the umbilicus shows an equivocal soft tissue mass within the mesentery. This could easily be mistaken for an unopacified loop of the small bowel.FIGURE 2Fig. 2: A CT image of the pelvis shows a possible soft tissue mass (arrowhead) just medial to the opacified distal right ureter.FIGURE 3Fig. 3: An In-111 octreotide scan at 24 hours shows normal uptake in the liver and spleen. Abnormal uptake is present in the midabdomen, corresponding to the mesenteric soft tissue mass on seen on the CT.FIGURE 4Fig. 4: (A) An In-111 octreotide scan at 24 hours shows additional foci in the right iliac fossa and adjacent to the right superolateral wall of the bladder. (B) A CT scan shows no abnormality of the terminal ileum.