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Colonic Malignant Melanoma: 18F-FDG PET/CT Findings


  • Eser Kaya
  • Tamer Aksoy
  • Ahmet Levent Güner
  • Hakan Temiz
  • Erkan Vardareli

Received Date: 06.02.2018 Accepted Date: 13.07.2018 Mol Imaging Radionucl Ther 2018;27(3):144-145 PMID: 30317855

Primary malignant melanoma occurs most often in the skin and much less frequently in the choroid layer of the eyes, in the leptomeninges, oral cavity, nasal mucosa, pharynx, esophagus, bronchus, under the nail and vaginal or anorectal mucosa. Primary melanoma of the gastrointestinal tract has been confirmed for lesions occurring in the esophagus, stomach, small bowel, and anorectum through several published reports, as these are the areas where melanocytes normally exist. The occurrence of primary malignant melanoma in the colon is relatively rare, because melanocytes are embryologically absent in the large bowel. Herein we report a patient whose colonic malignant melanoma was diagnosed and disseminated metastatic lesions were revealed with 18F-FDG PET/CT scan. There were multiple nodular lesions showing increased 18F-FDG uptake in both lungs. There was a soft tissue lesion with slightly increased 18F-FDG uptake, which extended to the intraluminal region of the thoracic esophagus. Increased metabolic activity was detected in the asymmetric stomach wall thickening site and in a soft tissue lesion located on the gall bladder wall that was filling the lumen. Multiple hypodense/hyper-metabolic lesions were identified in the liver. Multiple hyper-metabolic polypoid soft tissue lesions were visualized in almost the entire colonic segments. Multiple hyper-metabolic peritoneal implants were noted in all abdominal quadrants. Increased 18F-FDG uptake was detected at the right surrenal gland soft tissue lesion. There was a hyper-metabolic soft tissue lesion on the posterior wall of the rectum. Hyper-metabolic lytic lesions were seen at the thoracal and lumbar vertebrae, left scapula, left iliac bone, sacrum and left femur. There was no evidence of 18F-FDG avid skin lesions in both attenuation corrected and non-corrected images.

Keywords: Colon, malignant melanoma, 18F-FDG PET/CT


Informed Consent: Consent form was filled out by all participants.

Peer-review: Externally and internally peer-reviewed.

Authorship Contributions

Surgical and Medical Practices: E.K., T.A., A.L.G., H.T., E.V., Concept: E.K., T.A., Design: E.K., Data Collection or Processing: E.K., Analysis or Interpretation: E.K., T.A., E.V., Literature Search: E.K., Writing: E.K., T.A.

Conflict of Interest: No conflict of interest was declared by the authors.

Financial Disclosure: The authors declared that this study has received no financial support.

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