Primary colonic melanoma presenting as ileocecal intussusception: Case report and literature review

Figure 1 Computed tomography scan showing right lower intestinal intussusception (arrow) and multiple enlarged lymph nodes within the abdominal cavity and retroperitoneum.

Figure 2 Histopathologic findings of excised specimen. A: Microscopic examination showing tumor cells invading the colonic submucosa (arrow) (hematoxylin and eosin, × 100); B: Microscopic examination showing epithelioid and spindle tumor cells with melanin deposition in the cytoplasm (hematoxylin and eosin, × 200).

Figure 3 Immunohistochemistry findings of excised specimen. A-C: Tumor cells diffusely expressing S-100 (A), HMB-45 (B) and vimentin (C); D: 80% of tumor cells were positive for Ki-67 (immunohistochemistry, × 200).