Large-cell neuroendocrine carcinoma of the ampulla of Vater.

Large-cell neuroendocrine carcinoma is a high-grade neuroendocrine carcinoma, originally described in the lung. The tumor rarely occurs in extrapulmonary sites like the gastrointestinal tract, and only few examples have been described in the ampulla of Vater. A new case of large-cell neuroendocrine carcinoma of the ampulla of Vater in a 60-year-old man is reported. After pancreatoduodenectomy, macroscopic examination revealed ulcerated tumor in the region of the ampulla of Vater. Microscopically, the tumor exhibited organoid, predominantly nested growth pattern, consisting of large, polygonal cells with pleomorphic nuclei. Average number of mitoses was 36 per 10 high-power fields. Small and large areas of necrosis were identified. Immunohistochemically, the tumor cells were positive for synaptophysin, chromogranin A, PGP 9.5, neuron-specific enolase, pancytokeratin, CK8 and somatostatin and negative for CK7, CK20, S-100, TTF-1, HMB-45, CD117, E-cadherin and regulatory peptides. Ki-67 proliferative index was 41%. Histone deacetylase (HDAC) analysis showed almost identical results for HDAC1, HDAC2 and HDAC3--60, 60.3 and 61%, respectively. Two months after surgery, liver metastases occurred, confirming highly aggressive behavior of large-cell neuroendocrine carcinoma.