Large Primary Neuroendocrine Tumor of the Liver in a 57-year-Old Female Presenting With MSSA Bacteremia.

Primary neuroendocrine tumors (NETs) are rare forms of malignancy, representing just .5% of known cancers and having an overall incidence of 0.2/100,000. The most common sites of origin are bronchopulmonary and gastrointestinal, most commonly the appendix, pancreas, and ileum. We report the case of a 57-year-old female who was admitted for refractory MSSA bacteremia and several weeks of abdominal pain. CT imaging done on presentation demonstrated a 12.5 x 19.4 x 17.3 cm heterogeneous right liver mass with associated mass effect. The patient was taken to the operating room and a right hepatectomy and cholecystectomy were performed without complication. Histological examination revealed necrotic tumor in sheets and nests with marked nuclear pleomorphism. Immunohistochemistry demonstrated positive staining for pancytokeratin, synaptophysin, chromogranin, and TTF-1, consistent with undifferentiated NET. While rare, NETs can originate from a variety of organs outside the gastrointestinal and bronchopulmonary tract, including the liver.