Abstract:

A 63-year-old man presented to the emergency department with abdominal pain, episodes of bloody stool, nausea, and vomiting. Abdominal computed tomography showed lower intestinal intussusception and enlarged lymph nodes. Colonoscopic reduction was not possible. Exploratory laparotomy revealed a 15-cm mass comprised of the ileocecal region that had intussuscepted secondary to the small bowel. Palliative right hemicolectomy and resection of 60 cm segments of the small bowel were performed. Pathologic examination of the excised specimen revealed polypoid masses. There were 9 polyps, 1 in the ascending colon and the others in the ileum. Histopathological examination demonstrated obvious features of melanoma associated with epitheloid and spindle tumor cells and cytoplasmic melanin deposition. The tumor cells showed positivity for S-100, HMB-45 and Melan-A. Molecular examination revealed a c.1799> A (p.v600 A) mutation in exon 15 of the BRAF gene. The patient was re-examined and a nevus was found on the left anterior chest wall.

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