Endoscopic ultrasound features of rectal melanoma: A case report and review of literature

Figure 4 Hematoxylin-eosin staining and immunohistochemical staining. A: Islands of malignant cells with round or oval nuclei of variable size and deep staining of the nuclei, accompanied by mucosal infiltration; hematoxylin and eosin staining (200-fold magnification); B: HMB-45 melanocyte marker, positive in tumor cells and negative in the remaining epithelium; Immunohistochemistry (IHC) (200-fold magnification); C: S100 melanocyte marker, positive for tumor cells, negative for remaining epithelial cells; IHC (200-fold magnification).