Date Published: May 07, 2020
Publisher: Wolters Kluwer
Author(s): Rahul Chaudhari, Katherine Murphy, Stephen Schwartz, Jigisha Chaudhari, Immanuel Ho, Frederick Nunes.
Hepatoid adenocarcinoma (HAC) is an uncommon and aggressive type of adenocarcinoma, typically affecting the middle-aged and elderly. The morphological features of the HAC resemble hepatocellular carcinoma. Presenting symptoms may include upper abdominal pain, hematemesis, back pain, and palpable abdominal mass. HAC has no proven therapy, and the prognosis is extremely poor. Early surgical removal with chemotherapy remains the standard of care. We describe one of the youngest patients in the literature with HAC who presented with acute pancreatitis. The diagnostic workup was confused by diffuse lymphadenopathy and elevated β-human chorionic gonadotropin making lymphoma and germ cell tumor likely possibilities until immunohistochemistry confirmed the diagnosis.
Hepatoid adenocarcinoma (HAC) is a rare extrahepatic subset of adenocarcinoma associated with elevated α-fetoprotein (AFP). It is often metastatic at the time of diagnosis and carries a poor prognosis overall. The morphology of HAC closely resembles that of hepatocellular carcinoma (HCC), both of which commonly produce AFP presenting a diagnostic challenge. The diagnosis is usually made by hematoxylin and eosin staining and immunohistochemical (IHC) staining. HAC typically presents in the fourth to sixth decade. Presenting symptoms include upper abdominal pain, hematemesis, back pain, weakness, and palpable abdominal mass. We present one of the youngest cases of HAC reported in the literature involving a 28-year-old man with acute pancreatitis making it a rare presenting symptom.
A 28-year-old previously healthy white man of eastern European descent presented with a 2-week history of vomiting, anorexia, and abdominal pain. Physical examination was significant for mild tenderness in the epigastrium and left upper abdomen. Routine laboratory investigations were remarkable for abnormal liver blood tests—aspartate aminotransferase was 150 U/L, alanine aminotransferase was 387 U/L, alkaline phosphatase was 234 U/L, and total bilirubin was 2.5 mg/dL. Lipase was elevated at 1132 U/L and lactate dehydrogenase was 391 mg/dL. Abdominal ultrasound revealed lymphadenopathy posterior to the pancreatic head and dilatation of the proximal extrahepatic bile duct up to 11 mm.
HAC was first reported by Bourreille et al in 1970 after which Ishikura et al proposed the term “HAC of the stomach” because of its morphologic similarity to HCC. HAC constitutes 0.38%–1.6% of all gastric cancers, with an incidence of 0.58–0.83 cases per million inhabitants.1–4 Men are more commonly affected than the women.3 The characteristic features of HAC are hepatoid differentiation of cancer cells, the production of large amounts of AFP, and coexistence of both adenocarcinomatous and hepatocellular differentiation.2 The stomach is most commonly involved by HAC; however, other organs such as ovaries, lungs, urinary bladder, gallbladder, pancreas, uterus, testis, and retroperitoneum have also been reported to be involved.5 Patients with HAC frequently present with liver metastases.6
Author contributions: R. Chaudhari, K. Murphy, S. Schwartz, and J. Chaudhari wrote the manuscript. F. Nunes and I. Ho approved the final manuscript. R. Chaudhari is the article guarantor.