Malignant gastrointestinal melanoma is usually a metastatic lesion. We report the case of a 67-year-old female patient who presented with intermittent abdominal pain, fever, rigor and diarrhoea. CT scan of the abdomen revealed a large mass at the right iliac fossa with features concerning for intra-abdominal abscess. Exploratory laparotomy confirmed the preoperative diagnosis of abscess, and a right hemicolectomy was performed. Histopathological examination of the surgical specimen was indicative of malignant melanoma, and immunohistochemical examination showed positivity to S100 protein, Melan-A, HMB-45 and vimentin. A series of postoperative clinical, laboratory and imaging examinations revealed no suspicious lesions in the skin, eye, leptomeninges or other sites. Therefore, the diagnosis of primary colonic melanoma was confirmed. Only 36 additional cases of primary colonic melanoma have been reported to date. These rare neoplasms are challenging to diagnose and usually require a multidisciplinary treatment approach, including surgery, chemotherapy and possibly immunotherapy or radiotherapy.
- surgical oncology
- gastrointestinal surgery
- general surgery
- colon cancer
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Contributors Study concept and design, acquisition of data, analysis and interpretation of data, drafting of the manuscript, critical revision of the manuscript for important intellectual content and final approval of the version to be submitted: IAZ, SM, KSM, VNP.
Funding This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.
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