Primary hepatic neuroendocrine neoplasms: imaging characteristics and misdiagnosis analysis.

Objective: To analyze the CT and MR features of Primary hepatic neuroendocrine neoplasms (PHNENs) in order to enhance the diagnostic accuracy of this disease.

Methods: A retrospective analysis was conducted on patients diagnosed with hepatic neuroendocrine neoplasms, excluding other sites of origin through general examination and postoperative follow-up. The CT and MR signs were analyzed according to the 2018 version of Liver Imaging Reporting and Data System (LI-RADS), along with causes of misdiagnosis.

Results: Twelve patients, including 6 males and 6 females, were enrolled in this study. There was no significant increase in liver tumor markers among all cases. Most masses were multiple (9/12), exhibiting low attenuation on pre-contrast CT scans, T1-hypointense signal, T2-hyperintense signal, and restricted diffusion. The majority of these masses (7/10) demonstrated similar rim arterial phase hyper-enhancement as well as peripheral "washout" during venous portal phase and delayed phase imaging. Three cases had incomplete capsules while one case had a complete capsule. Cyst/necrosis was observed in 7 out of all cases following administration of contrast agent, with 5 mainly distributed in the periphery. All masses lacked fat, calcification, vascular or bile duct tumor thrombus formation.

Conclusion: The imaging findings associated with PHNENs possess certain specificity, often presenting as multiple masses within the liver accompanied by peripheral cyst/necrosis, similar rim arterial phase hyper-enhancement during venous portal phase and delayed phase imaging.