Ultrasonographic characteristics of hepatic neuroendocrine neoplasm

Objective To analyze the features of hepatic neuroendocrine neoplasm (HNEN) with conventional ultrasound and contrast-enhanced ultrasound sonography (CEUS), and to evaluate the value in the diagnosis and differential diagnosis of HNEN by ultrasound. Methods Fifty patients of HNEN confirmed pathologically or clinically were enrolled. All patients underwent conventional ultrasound and CEUS. Among the patients, 5 cases were primary hepatic neuroendocrine neoplasm (PHNEN), and 45 cases were metastatic hepatic neuroendocrine neoplasm (MHNEN). Conventional ultrasound and CEUS features of HNEN were analyzed and the distinctions between PHNEN and MHNEN were compared. Results Baseline ultrasound showed that 37 (74%) HNEN were multiple lesions located in liver, 23 (46%) lesions with hyperechoic appearance, 35 (70%) lesions with homogeneous echoic, 28 (56%) lesions were clearly marginated, 8 (16%) lesions were surrounded by acoustic halo, and 12 (24%) lesions with posterior echo attenuation. CEUS showed that the majority of HNEN exhibited the enhanced pattern of rapid wash-in and wash-out . Forty-six (92%) lesions showed hyper-enhancement in the arterial phase, 44 (88%) lesions showed iso-enhancement in the portal phase, and 47(94%) lesions showed hypo-enhancement in the late phase.Feeding vessels were observed in 31 (62%) lesions, intralesional non-enhancement zone was observed in 17(34%) lesions, and capsule enhancement in the delay phase was found in 10(20%) lesions. MHNEN had smaller diameter [ (3.92±2.77)cm vs (12.82±8.85)cm, P=0.004] and less likely to present cystic structure intralesional than PHNEN (1/45 vs 2/5, P 0.05). Conclusions HNEN has a certain characteristic that can be identified on ultrasonography. Ultrasound can provide some valuable information to diagnose HNEN. While it′s difficult to differentiate PHNEN and MHNEN owing to their similar ultrasonographic characteristics. Key words: Ultrasonography; Contrast-enhanced ultrasound; Liver neoplasms; Neuroendocrine neoplasms