Primary Neuroendocrine Tumor in the Liver

Abstract

Neuroendocrine tumors (NETs) are rare and typically have an indolent course. NETs usually arise from pancreas or small bowel and metastasize to the liver. Only 25% of NETs are hormone producing. Primary hepatic NETs are very rare, accounting for 0.3% of all NETs. As such, the clinical presentation is not well recognized. The following case describes the presentation of a primary hepatic NET and management of its complications. A 44 year-old male presented with 1 week of right upper quadrant pain and jaundice. He reported a month long history of dyspepsia refractory to PPI, early satiety, and 10-pound weight loss. He had evidence of hepatocellular and cholestatic liver injury (Table 1). Imaging showed biliary obstruction due to a 5 cm x 10 cm x 4 cm heterogeneous, multicystic, enhancing mass in the left hepatic lobe. Ultrasound suggested hepatocellular carcinoma, while CT and MRI raised concern for intraductal lesions and cholangiocarcinoma (Figures 1-2). On day 2, ERCP identified 2 filling defects in the common bile duct (CBD), likely causing intermittent obstruction. CBD brushings were negative for malignant cells. The obstruction was treated with biliary sphincterotomy and placement of a 8.5 Fr by 9 cm stent into the CBD. On day 4, EUS showed a mixed cystic and solid mass lesion in the left hepatic lobe along with a 4 cm long intraductal mass - of the same density - extending from the common hepatic duct to the CBD. The left intrahepatic bile ducts were diffusely dilated around the hepatic mass. The common hepatic duct and CBD were dilated to 18mm secondary to the intraductal mass. On day 5, ERCP was repeated due to evidence of persistent biliary obstruction on EUS and fluctuating bilirubin (Table 1). This second ERCP showed filling defects at the hepatic duct bifurcation and proximal CBD. The left hepatic duct was completely obstructed (Figure 3). The previous biliary stent was replaced with an 8.5 Fr by 15 cm stent into the right hepatic duct, and biliary obstruction was relieved. Biopsies from the EUS showed a low-grade NET. Chromogranin A was elevated at 2111 ng/mL and 5-HIAA was within the reference range. The patient was discharged with plans for an octreotide scan and follow up with surgical oncology.Figure: Hepatic Mass on CT.Figure: Hepatic Mass on T2 weighted MRI.Figure: Biliary Tree on ERCP #2, with complete obstruction of left hepatic duct.Table: Table. Liver Panel Through Treatment CourseNETs are rare and can have a variety of presentations, based on their origin and activity. This case highlights one of the few documented occurrences of biliary obstruction as the presenting feature of a primary hepatic NET.