A 70-year-old man comes to the office due to abdominal pain that began 1 month ago. He has also experienced fatigue and weight loss. He has no chronic medical conditions and takes no daily medications. The patient worked in a factory that produced polyvinyl chloride for several decades and is now retired. Physical examination shows hepatomegaly. Imaging demonstrates a liver mass, which is subsequently resected. Immunohistochemical staining of the tumor cells is positive for CD31. Which of the following is the most likely diagnosis?

Question

A 70-year-old man comes to the office due to abdominal pain that began 1 month ago.  He has also experienced fatigue and weight loss.  He has no chronic medical conditions and takes no daily medications.  The patient worked in a factory that produced polyvinyl chloride for several decades and is now retired.  Physical examination shows hepatomegaly.  Imaging demonstrates a liver mass, which is subsequently resected.  Immunohistochemical staining of the tumor cells is positive for CD31.  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

Hepatic angiosarcoma is a rare, aggressive vascular malignancy. It usually presents in older men (age >60) and is associated with carcinogen exposure. Implicated chemicals include vinyl chloride (eg, exposure during production of polyvinyl chloride, a widely used plastic), arsenic (eg, exposure to pesticides), and Thorotrast (formerly used radioactive contrast medium). Clinical manifestations can include abdominal pain, fatigue, weight loss, and hepatomegaly, as well as intraabdominal hemorrhage (caused by tumor rupture). Angiosarcomas are derived from endothelial cells. In the liver, they appear grossly as poorly circumscribed, hemorrhagic lesions. Microscopic examination typically shows vascular structures lined by atypical (eg, hyperchromatic, pleomorphic) cells that express CD31 (ie, platelet endothelial cell adhesion molecule [PECAM1]). PECAM1 is expressed on the surface of endothelial cells and functions in leukocyte migration through the endothelium. (Choice A) Hepatic cavernous hemangiomas are common benign vascular lesions. Microscopy shows a well-circumscribed proliferation of dilated vascular structures that are lined by endothelial cells lacking atypia. Although cavernous hemangiomas express CD31, patients are typically asymptomatic (eg, lesion incidentally found on imaging). (Choice B) Cholangiocarcinomas are rare, malignant tumors derived from bile duct epithelium. They may present with abdominal pain and weight loss, but CD31 expression would not be expected. (Choice D) Hepatoblastomas are malignant liver tumors derived from immature, multipotent cells. Most cases occur in children age <5. (Choice E) Hepatocellular adenomas are benign liver tumors derived from hepatocytes. Although clinical manifestations may include abdominal pain, they typically present in young women (ie, reproductive years) and are associated with oral contraceptives or anabolic steroid use. (Choice F) Kaposi sarcoma is a vascular neoplasm associated with human herpesvirus 8 that can involve the liver. Microscopy typically shows proliferation of spindle-shaped endothelial cells (ie, CD31 positive) with slit-like vascular spaces. However, it typically presents in immunocompromised patients (eg, those with AIDS) and often initially involves the skin (eg, purple papules on the lower extremities). Educational objective: Hepatic angiosarcoma is an aggressive vascular malignancy associated with exposure to carcinogens (eg, vinyl chloride). The tumor cells express CD31 (ie, platelet endothelial cell adhesion molecule [PECAM1]), an endothelial cell marker important for leukocyte transmigration.

A 70-Year-Old Man Comes to the Office Due to Abdominal