Primary hepatic neuroendocrine tumor with exophytic growth: report of a case with diagnosis by fine needle aspiration biopsy

Primary hepatic neuroendocrine tumor with exophytic growth is a unique entity. A 74-year-old man presented to our hospital with abdominal discomfort. Diagnostic imaging procedures revealed a 15 x 10-cm mass in the liver with exophytic growth. The tumor was adjacent to the stomach, and clinical suspicion of gastrointestinal stromal tumor of the stomach was very strong initially. The cytologic and immunocytochemical examination of aspirated material showed features similar to those of neuroendocrine tumor. Systemic staging procedures showed no evidence of metastasis or other primary site. The histopathologic results of the excised tumor confirmed the cytologic diagnosis. Primary neuroendocrine tumor with exophytic growth is a rare entity and can be diagnosed with cytology and immunocytochemistry.