Figure 3From: Primary malignant melanoma of the duodenum without visible melanin pigment: a mimicker of lymphoma or carcinomaImmunohistochemical stains (Envision, Objective × 40). (A) The tumor cells were positive for HMB45 in cytoplasm; (B) The tumor cells were positive for Melan-A in cytoplasm; (C) The tumor cells were positive for protein S-100 protein in both nucleus and cytoplasm; (D) Ki-67 immunostaining showed a proliferative index of 60%.Back to article page