This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Pathology
[{'content': 'Migratory thrombophlebitis is caused by \nSelect and explain. \nA. Pancreatic carcinoma, B. Colonic carcinoma, C. Nasopharyngeal carcinoma, D. Meningioma', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Carcinomas of the pancreas typically remain silent until theirextension impinges on some other structure. Pain usually is thefirst symptom, but by that point these cancers are oftenbeyond cure. Obstructive jaundice can be associated withcarcinoma in the head of the pancreas, but it rarely drawsattention to the cancer soon enough for timely intervention.Weight loss, anorexia, and generalized malaise and weaknessare manifestations of advanced disease. Migratory thrombophlebitis (Trousseau syndrome) occurs in about 10% of patients and is attributable to the elaboration of platelet aggregating factors and pro-coagulants from the tumor or its necrotic products.Robbins Basic pathology, 9th edition, pg no.654', 'role': 'assistant'}]