We present the case of a pregnant woman with aplastic anemia. The 22-year-old patient presented with 27 weeks of gestation and lymphoproliferative syndrome at the Instituto Nacional de Perinatología in Mexico City. The bone marrow biopsy confirmed the diagnosis and the immunophenotype was negative for malignancy. The treatment consisted of transfusions and planned birth at 35 weeks. Afterwards, the patient was referred to a bone marrow transplant unit.

Fetal ovarian cysts are the most frequent fetal abdominal tumors. With an incidence of 1 in 2 500 live births and unilateral predominance, these cysts are generally diagnosed after 29 weeks’ gestation, when the hypothalamic-pituitary-gonadal axis has reached maturity. They are usually small, self-resolving and have limited clinical impact. Follow-up every two weeks is recommended; cysts larger than 4 cm have the highest complication rates. If it consistently presents the features of a simple cyst, it is recommended to wait until term for resection. We report the case of a fetus with an abdominal tumor diagnosed as fetal cyst, which prompted weekly monitoring of fetal hemodynamic parameters and cesarean section at 37 weeks. The newborn underwent laparotomy with left salpingo-oophorectomy. Fetal ovarian cyst torsion was diagnosed by histological examination.