Size-biology paradox in ampullary tumours - large-cell neuroendocrine carcinoma of the ampulla of Vater: A case report

Figure 1 Contrast-enhanced coronal computed tomography images. A: Dilatation of the common bile duct (yellow arrow) with abrupt distal cut-off at the level of the ampulla (green arrow), suggestive of ampullary pathology; B: Associated dilatation of the pancreatic duct (orange arrow), consistent with a double duct sign.

Figure 2 Positron emission tomography/computed tomography. Axial imaging demonstrates focal fluorodeoxyglucose uptake at the ampulla of Vater (yellow arrow), consistent with a metabolically active ampullary lesion.

Figure 3 Histopathological findings of large-cell neuroendocrine carcinoma of the ampulla of Vater (× 200). A: Neoplastic cells with a high nuclear-to-cytoplasmic ratio arranged in solid sheets; B: Focal tubular formation within the tumour, indicating an adenocarcinoma component; C: Diffuse immunohistochemical positivity for chromogranin; D: High Ki-67 proliferation index consistent with a high-grade neuroendocrine carcinoma.