case_images: PMC11164300_01
case_images: Plain abdominal X-ray showing distention at the proximal and air-free level at the distal loop
case_images: ijp-19-114-g001.jpg
case_images: PMC11164300_01_ijp-19-114-g001.jpg
case_images: F1
case_images: The abdominal ultrasound conducted in the emergency department revealed "segmental intestinal dilation with wall thickening"; a plain abdominal X-ray revealed dilated proximal bowel loops and air-free level in the distal part (Figure 1).
case_images: Emergent laparotomy showing a bulky tumor in the small intestine
case_images: ijp-19-114-g002.jpg
case_images: PMC11164300_01_ijp-19-114-g002.jpg
case_images: F2
case_images: The intraoperative finding was a bulky greyish tumor (7 x 6 cm) of the small bowel with focal ulceration and necrosis, which extended up to the serosal layer (Figure 2).
case_images: Hematoxylin-eosin section (H&E) and immunohistochemical study of malignant melanoma. H&E staining showing malignant spindled-shaped and epithelioid cells with high cellularity (A). An immunohistochemical study showing strong positive immunoreactivity for HMB-45 (B) and a partial positive reaction for Melan-A (C) and S-100 (D)
case_images: ijp-19-114-g003.jpg
case_images: PMC11164300_01_ijp-19-114-g003.jpg
case_images: F3
case_images: Histological findings showed a proliferation of spindled-shaped and epithelioid cells with irregular nuclear borders, prominent nucleoli, and a few cells with intracytoplasmic melanin pigment (Figure 3). The immunohistochemical study revealed strong positivity for HMB-45 in nearly all the tumoral cells with focal positivity of Melan-A and S-100 protein (Figure 3).
case_images: Immunohistochemical study to rule out other mimics. Immunohistochemical stains showing negative immunoreactivity for CD117 (A), DOG1 (B), chromogranin (C), and cytokeratin (D)
case_images: ijp-19-114-g004.jpg
case_images: PMC11164300_01_ijp-19-114-g004.jpg
case_images: F4
case_images: CD117, DOG1, chromogranin, and cytokeratin was negative in the tumoral cells, which helped to rule out the possibility of a GIST, neuroendocrine tumor, and poorly differentiated carcinomas (Figure 4).