S3186 The Imaging Negative Hepatic Lesions: A Rare Case of Infiltrative Hepatocellular Carcinoma

Abstract

Introduction: Hepatocellular Carcinoma (HCC) is the 6th most common cancer and the 4th leading cause of cancer-related death worldwide. The infiltrative subtype is the most difficult to diagnose with imaging because of its inherently ill-defined micronodules involving a segment or entire hepatic parenchyma without a distinguishable mass. Prognosis is poor and estimated at a 5-year survival rate of < 20%. Diagnosis of HCC requires a sensitive imaging test. In situations where imaging is not able to identify a mass, EUS-FNA has been shown to have a higher detection rate. Case Description/Methods: A 61-year-old female with a past medical history of HCV cirrhosis with sustained virology response (SVR), presented with abdominal pain and worsening lower extremity edema. Remarkable examination findings include a distended abdomen and bilateral pitting lower extremity edema. Significant work up showed platelet of 109k/cmm (150-440), AST of 159 unit/l (15-37), total bilirubin of 1.2mg/dl (0.2-1.0), AFP of >20,000ng/ml (0.5-8.0), peritoneal fluid cytology was negative. A right upper quadrant ultrasound, CT, and MRI showed no hepatic mass, Fig CD. With markedly elevated AFP and a high suspicion for HCC, the patient had EGD-EUS guided fine-needle aspiration showing multiple infiltrative hepatic lesions, Fig E. The biopsy report showed malignant cells positive for AFP with cells reactive for glypican-3 and negative for Hep-Par1 (Fig A), supporting the diagnosis of HCC. The patient was referred to oncology and a month later, she died. Discussion: SVR is associated with decreased risk of HCC, however, with a cirrhotic liver, patients still have an absolute risk of developing HCC. Initial diagnosis of HCC can be obtained non-invasively using abdominal ultrasound, CT, MRI, and EUS-FNA. Abdominal ultrasound is the best imaging modality recommended for HCC surveillance because it is readily available. However, its sensitivity for detecting early HCC is about 47%. AFP cut-off level of > 20ng/ml has a sensitivity of about 60% with low specificity. A level of > 400ng/ml is diagnostic for HCC with a specificity of almost 100%. Incremental changes in AFP are associated with an increased mortality rate. The median survival rate of infiltrative HCC with AFP of > 400 is estimated to be about 5 months. EUS is superior to CT in detecting small hepatic lesions, with a sensitivity of 100% compared to 71% of CT. We recommend that EUS be considered an integral modality while investigating the diagnosis of infiltrative HCC.Figure 1.: Fig A showing Hepatocellular carcinoma, 200x. Glypican-3 immunostain shows strong, diffuse staining in HCC (A). Background non-neoplastic liver is negative (B). Fig C is the cirrhotic liver with no identifiable mass. Fig D shows fluid around the liver and spleen. Fig E is the EUS showing multiple infiltrative hepatic lesions.