Increased Colonic Fluorodeoxyglucose Uptake in Melanosis Coli—A Case Series of Three Patients

We report 3 Japanese cases with increased colonic 18-fluorodeoxyglucose (FDG) uptake in association with melanosis coli. Case 1: A 56-year-old woman received 18-FDG positron emission tomography (PET) for comprehensive medical checkup. Case 2: A 79-year-old man received FDG-PET for follow-up evaluation for intestinal cancer. Case 3: A 51-year-old woman received FDG-PET for medical checkup. Each showed increased cecal and/or ascending colonic uptake without any colonic wall changes. Colonoscopy detected melanosis coli where FDG uptake was demonstrably increased. Neither malignancy nor inflammatory response was confirmed. Succeeding follow-ups showed neither malignant nor inflammatory lesions in any of the patients.