BackgroundMesenteric cyst is a rare clinical entity especially in pregnancy; therefore, few cases have been reported in the literature. The standard method of their treatment is surgical excision either with laparotomy or laparoscopy. In addition, mesenteric vein thrombosis is a rare and life-threatening condition in pregnancy and needs immediate treatment because it can lead to intestinal necrotic ischemia. This is the first report of the coexistence of mesenteric cysts and mesenteric vein thrombosis during gestation.Case presentationA 27-year-old Greek woman, gravida 2 para 1, presented at 10 weeks’ gestation to the Emergency Unit of our hospital complaining of diffuse abdominal pain which deteriorated the last 3 days, which was localized in her right iliac fossa, along with vomiting. She had undergone open laparotomy and right salpingo-oophorectomy at the age of 23 due to an ovarian cyst. Besides this, her personal and family medical history was unremarkable. She had never received oral contraceptives or any hormone therapy. On arrival, a clinical examination revealed tenderness on palpation of her right iliac fossa, without rebound tenderness or muscle guarding. Within 10 hours of hospitalization, her symptoms deteriorated further with rebound tenderness during the examination, tachycardia, and a drop of 12 units in her hematocrit value. An emergency laparotomy was performed. Two mesenteric cysts and a 60 cm necrotic part of her intestine were revealed intraoperatively. In the postoperative period, she complained of acute abdominal pain, tachycardia, and dyspnea. Computed tomography imaging revealed mesenteric vein thrombosis and pulmonary thromboembolism. She was treated with low molecular weight heparin and she was discharged on the 11th postoperative day.ConclusionsTo the best of our knowledge, this is the first report in the literature of a simultaneous mesenteric cyst and mesenteric vein thrombosis in pregnancy. It is known that pregnancy is a state of hypercoagulation and clinicians should bear in mind this rare clinical condition in their diagnostic algorithm for acute abdominal pain.