Comparison analysis of ultrasonographic characteristics of hepatic neuroendocrine neoplasm with different primary sites and pathological grades

Abstract

Objective To investigate the ultrasonography discrepancy of hepatic neuroendocrine neoplasm (hNEN) derived from different primary locations and pathological grades. Methods From August 2010 to April 2016, 50 consecutive patients with 54 hNENs confirmed by pathology and imaging diagnosis underwent baseline ultrasound (BUS) and contrast-enhanced ultrasound (CEUS) in the First Affiliated Hospital of Sun Yat-sen University were enrolled in the retrospective study. On the basis of primary sites, all hNENs were divided into three groups: pancreas, gastrointestinal tract and other location groups. According to the pathological grading, the hNENs were divided into hNET (hepatic neuroendocrine tumor) group and hNEC (hepatic neuroendocrine carcinoma) group. The imaging features of BUS and CEUS were retrospectively investigated and the ultrasonography discrepancy of hNEN derived from different primary focus and pathological grades were compared. Results ①Comparison of hNEN derived from different primary sites: hNEN derived from pancreas and gastrointestinal tract were smaller than hNEN derived from other sites[ (3.8±2.6)cm vs (8.7±7.0)cm, P=0.037; (2.9±2.1)cm vs (8.7±7.0)cm, P=0.005], but the difference between the pancreas and gastrointestinal tract was not statistically significant (P=1.0). As for the pattern of CEUS enhancement, hNEN derived from pancreas and gastrointestinal tract usually showed homogenous enhancement (13/19, 15/23) while hNEN derived from other primary sites usually showed heterogeneous enhancement (10/13), and the difference was statistically significant (P=0.025). ②Comparison of hNET and hNEC: the distinction of enhancement level in the portal phase of contrast-enhanced ultrasound was statistically significant (P=0.033). All hNEC appeared hypo-enhancement, while a small part of hNET(7/31) appeared iso-enhancement.More hNEC lesions showed heterogenous enhancemnt than hNET in the arterial phase (14/21 vs 9/31, P=0.007), and there were less hNEC lesions presented tumor bleeding vessels than hNET (8/21 vs 22/31, P=0.019). Conclusions hNEN derived from pancreas and gastrointestinal tract are in a manner similar to hNEN derived from other primary sites on ultrasonography, so it′s difficult to identify in ultrasound. The ultrasonographic features of hNEC are more resemble to malignancy and it can be distinguished from hNET. Key words: Ultrasonography; Liver neoplasms; Neuroendocrine neoplasms