The aim of this study was to describe the case report of a 33-year-old girl with portal vein thrombosis. J.S.D.F., 33 years old, female, previously healthy, with a personal and family history negative for thromboembolic phenomena, without comorbidities, started with severe abdominal pain in the mesogastric region, radiating to HCD and back, associated with vomiting. Smoking active for about 20 years and using OC for 2 years. In view of the symptoms, she sought emergency services, where the first suspicion would be pancreatitis. Initial tests plagued leukocytosis. GUS of the total abdomen with doppler and CT of the abdomen showed the presence of thrombus in the right portal vein, with no other alterations. Rocefin® and metronidazole as an initial measure in the service began in addition to full coagulation with Clexane®. It showed clinical and laboratory improvement, with a reduction of leukocytes. The patient remained hospitalized in a hospital for 22 days to investigate the etiological cause. After of hospitalization, the patient was released with medical discharge, with guidelines for seeking the hematology service. During the investigation consultations, the results of the requested tests were negative for the diagnostic suspicions of nocturnal paroxysmal hemoglobinuria and chronic myeloproliferative disease. After 6 months of follow-up, she was discharged from the hematology service because she did not present a suspected disease and classified the cause of thrombolytic event as idiopathic associated with the combined use of OC and smoking.