Purpose  To discuss the ultrasound characteristics of pancreatic neuroendocrine neoplasms (pNEN) with liver metastasis and the significance of postoperative ultrasound examination.

  Methods  From January 2011 to December 2020 in Tianjin Medical University Cancer Institute& Hospital, we collected the ultrasound follow-up data (characteristics of the pancreatic and liver metastasis tumors) of 225 patients with pNEN confirmed by pathology and analyzed the ultrasound characteristics of pancreatic primary tumor and hepatic metastasis tumor.

  Results  Liver metastasis occurred in 81 out of 225 patients with pNEN. There were significant differences in the pancreatic tumor margin and liver metastasis among pNEN lesions with different pathological classifications. Patients with pNEN who did and did not have liver metastasis exhibited significant differences in terms of sex, obstructive jaundice occurrence, maximum diameter of pancreatic tumors, edge, internal calcification, and regional lymph node metastasis (P<0.05). Logistic analysis results: obstruction jaundice, maximum diameter of pancreatic tumors, pathological type classification, and internal calcification are independent risk factors for liver metastasis in patients with pNEN. Compared to patients with simultaneous liver metastases, those with metachronous liver metastases who had undergone complete resection of the primary focus were relatively younger; moreover, in these cases, liver metastases were often single, mostly located in the right lobe, more common in distribution type Ⅰ, maximum diameter was ＜3 cm, the edge was often clear, and there were fewer pNEN related deaths. These differences were statistically significant (P<0.05).

  Conclusions  The occurrence of liver metastasis in patients with pNEN is related to the pathological classification. Obstructive jaundice, the maximum diameter, pathological classifications, and calcification in pancreatic lesions are independent risk factors for liver metastasis in patients with pNEN. The patients with metachronous liver metastases as showed in ultrasonographic features are more eligible for surgical treatment and prognosis are better than those with simultaneous liver metastases. Understanding the ultrasonographic features of pNEN pancreatic tumor and liver metastasis has great clinical significance for the diagnosis, follow-up, and treatment of pNEN with liver metastasis.