Histopathologic evaluation showed a high-grade malignant neoplasm involving the bowel wall which was labeled for S100 protein and markers of melanocytic differentiation; Melan-A indicating the definitive diagnosis of malignant melanoma of the second portion of duodenal mucosa.<h4>Conclusions</h4>In patients with a history of iron deficiency anemia, any GI symptom should be evaluated carefully. This evidence concerns the gene MLANA and cancer.