2328 Ectopic Liver: A Silent Killer

Abstract

INTRODUCTION: We present a rare case of Ectopic Liver (EL) tissue along the pancreatic tail, that developed into HCC. Based on our research, there are only 4 reported cases of primary HCC in EL tissue around the pancreas. Our case originates in the retroperitoneum near the pancreas. CASE DESCRIPTION/METHODS: 70 y.o Female with Tuberous Sclerosis was referred for an incidental finding of an abdominal mass. She was seen by her PCP for back pain and difficulty ambulating. Physical exam showed chronic facial rash. Abdominal exam was negative for a palpable mass, tenderness, guarding or rebound. Labs revealed normal LFTs and normocytic anemia. Viral hepatitis panel was negative. MRI abdomen showed a 6.8 × 7 cm mass in the LUQ with a central cystic cavity and a surrounding solid component.The mass abuted the pancreatic tail and loops of bowel and was of unclear origin. EUS showed a normal appearing pancreas. A hypoechoic mass with cystic and solid components was noted next to the pancreas. FNA was performed. Immunohistochemical staining was positive for Hepatocyte specific antigen (HSA), supporting hepatic origin and CK7 highlighting the presence of a bile ductules. This supported the diagnosis of hepatic tissue. Surgical resection was recommended. A 8 cm mass involving the splenic vein and pancreatic tail was noted and distal pancreatectomy and splenectomy was performed. Surgical pathology showed carcinoma with hepatic differentiation, most consistent with primary HCC, adherent to the pancreas, but not involving the pancreatic parenchyma. No benign liver tissue was identified. A diagnosis of HCC arising within and replacing a rest of ectopic liver was made. AFP post-op was normal. Post-op course was uneventful. DISCUSSION: EL is defined as liver tissue found outside and not in communication with the normal liver. It is susceptible to same diseases as normal liver and especially prone to malignancy, despite the lack of risk factors. Given the difference in arteriovenous and bile system, EL tissue may have longer exposure to carcinogens. MRI shows "post contrast peripheral solid enhancement" - suggestive of HCC with ectopic tissue enhancement in arterial phase, however is less highlighted compared to HCC in normal liver. AFP is > 20ng/mL in 60% cases. Surgical resection is the primary treatment with no reported tumor recurrence. Our case highlights the importance that any EL is at high risk for HCC development, despite the lack of risk factors and negative FNA biopsies and surgical therapy needs to be offered.