ACUTE PORTAL VEIN THROMBOSIS; MARKED LEUKOCYTOSIS; MILD THROMBOCYTOSIS; ELEVATED LIVER ENZYMES; This spontaneous report was received from literature. This report concerned a 48 year old male of unknown race and ethnicity. The patient's height, and weight were not reported. The patient's past medical history included: ex-alcoholic (He used to drink 12 beer cans every-other-day for the past year but quit two months before symptoms started) and concurrent conditions included: arterial hypertension. The patient received covid-19 vaccine ad26.cov2.s (suspension for injection, route of admin, and batch number were not reported, expiry: unknown) dose, frequency one total, start therapy date were not reported for prophylactic vaccination (series1). The batch number was not reported. The company is unable to perform follow-up to request batch/lot numbers. No concomitant medications were reported.  On an unspecified date patient presented to the emergency department (ED) with abdominal pain of two weeks. The pain was described as constant sharp, of moderate intensity, localized to the epigastrium, without radiation, not associated to meals and alleviated by Ibuprofen. The patient experienced acute portal vein thrombosis, marked leukocytosis of 22 x 10^3 U/L, mild thrombocytosis of 505 x 10^3 uL, and elevated liver enzymes, and was hospitalized (date unspecified). He denied fever, nausea, vomiting, appetite or weight loss, diarrhea, or gastrointestinal bleed. Laboratory data (dates unspecified) included: Alanine aminotransferase (NR: not provided) 101 U/L, Alkaline phosphatase (NR: not provided) 239 U/L, Aspartate aminotransferase (NR: not provided) 57 U/L, Bilirubin total (NR: not provided) Normal, CT scan (NR: not provided) right intrahepatic PVT wedge, Pancreatic enzymes were Normal, and Thrombophilia was Normal. Total bilirubin and pancreatic enzymes were all within normal limits. Treatment medications (dates unspecified) included: ibuprofen. The action taken with covid-19 vaccine ad26.cov2.s was not applicable. The outcome of the acute portal vein thrombosis, marked leukocytosis, mild thrombocytosis and elevated liver enzymes was not reported. The author emphasized PVT is an uncommon disease where the most predisposing etiologies are liver cirrhosis and hepatobiliary malignancies. The prevalence is estimated to be less than 1% in patients with compensated cirrhosis, however unknown in patients without cirrhosis Thrombophilia must always be excluded. Multiple vaccines against COVID-19 have been developed with the aim of controlling the current pandemic. Even-though the worldwide Immunization continues to have positive results, cases of vaccine-related thrombotic events have been documented. We may not conclude that our case is related to the vaccine, but after exclusion author can suspect that the vaccine is linked to this thrombotic event. This report was serious (Hospitalization Caused / Prolonged).; Sender's Comments: V0: 20211157301-COVID-19 VACCINE AD26.COV2.S- Acute Portal vein thrombosis, marked leukocytosis, mild thrombocytosis, elevated liver enzymes. This event(s) is considered unassessable. The event(s) has a compatible/suggestive temporal relationship, is unlabeled, and has unknown scientific plausibility. There is no information on any other factors potentially associated with the event(s).