Primary malignant melanoma of the liver: A case report

Figure 1 Contrast-enhanced abdominal CT scan showing an oval, low-dense, well-defined mass measuring 10. 1 cm × 12.8 cm in the right posterior lobe of the liver.

Figure 2 Gross appearance of the resected specimen showing the oval outline of tumor adjacent to normal liver tissue.

Figure 3 Microscopy showing diffusely infiltrating tumor cells (A) and fibrous tissues (B) between the lesion and normal hepatocytes with a few broken tumor cells through the capsule infiltrating the adjacent liver tissue (× 200), pleomorphic tumor cells with round, spindle-shaped and irregular morphologies(× 400) (C), and some tumor cells containing melanin deposition (× 200) (D).

Figure 4 Immunohistochemistry revealing tumor cells positive for vimentin (× 200) (A), melanoma-pan (× 400) (B), HMB45 (× 400) (C) and S-100 protein (× 200) (D).

Figure 5 Electron microscopy displaying occasional melanosomes in the cytoplasm (arrow).