Metastatic Rectal Carcinoid on In-111 Octreotide SPECT-CT Imaging

Abstract

A 65-year-old asymptomatic male who tested positive for fecal occult blood was found to have a rectal mass on colonoscopy. Staging workup included a CT scan of the abdomen which showed a neoplasm in the liver, with neuroendocrine features on fine needle aspiration. Planar 24 hours whole body In-111 octreotide scan showed a small focus of mildly increased activity in the lateral left lower chest, a very large focus of intense uptake in the liver, and 4 distinct foci of mild to moderately increased uptake in the lower abdomen and pelvis. SPECT-CT images localized these abnormalities to: focal uptake in the rectal wall thickening, 2 presacral lymph nodes, the liver mass, and multiple bone metastases (left ilium, L5 pedicle, and the left 6th rib). This rare case highlights the importance of SPECT-CT in staging carcinoid tumors with In-111 octreotide imaging.