Primary hepatic neuroendocrine tumor with a suspicious pulmonary nodule: A case report and literature review

BACKGROUND Primary hepatic neuroendocrine tumors (PHNETs) are extremely rare tumors originating from neuroendocrine cells. Due to lack of neuroendocrine symptoms and specific radiographic characteristics, PHNETs are challenging to differentiate from other liver tumors. CASE SUMMARY This case involved a 67-year-old male who was admitted with a discovered hepatic mass and a suspicious lung lesion. Primary hepatic carcinoma was initially speculated based on the characteristic magnetic resonance imaging findings. The patient underwent a laparoscopic right partial hepatectomy, and subsequent immunohistochemical examination revealed a HNET. To exclude other potential origins, a positron emission tomography-computed tomography scan and gastrointestinal endoscopy were performed, leading to a final diagnosis of PHNETs. Then we conducted a literature review using the PubMed database, identifying 99 articles and 317 cases related to PHNETs. The characteristics, diagnostic methods, and treatment of PHNETs have been described. Finally, we elaborate on the presumed origins, pathological grades, clinical features, diagnosed methods, and treatments associated with PHNETs. CONCLUSION The diagnosis of PHNETs was primarily an exclusionary process. A definitive diagnosis of PHNETs relied mainly on immunohistochemical markers (chromogranin A, synaptophysin, and cluster of differentiation 56) and exclusion of primary foci in other organs. Radical surgery was the preferred treatment for early-stage tumors.