Fig. 4From: Neuroendocrine tumor of the ampulla of Vater with distant cystic lymph node metastasis: a case reportMicroscopically, the tumor consists of a small-sized round cell proliferation with a solid nest pattern (a). The cyst preserved the structure of the lymph node and was the superior mesenteric lymph node metastasis of the tumor (b). Immunohistochemically, the resected specimen revealed that the tumor and lymph node metastases were positive for chromogranin A (c)Back to article page