Antenatal exposure to atenolol and retroperitoneal fibromatosis

We present a case of retroperitoneal fibromatosis in a fetus whose mother took atenolol during pregnancy. A 25-year-old obese woman was treated for hypertension with 100 mg atenolol daily from the second month until the end of pregnancy. At 29 weeks, echography disclosed a retroperitoneal mass and at 37 weeks, a boy was delivered. A biopsy of the tumor showed a fibromatosis with medullary compression, treated by antimitotics until 3 months of age. At the age of 4, the mass had disappeared but severe scoliosis was present. This in utero exposure to atenolol drew our attention because the retroperitoneal localization of the tumor is similar to that of fibroses reported in adults after exposure to atenolol and for other reasons: transplacental carcinogenesis has been demonstrated in humans, at least for diethylstilboestrol, atenolol crosses the placental barrier, the drug was taken during nearly the whole pregnancy, and retroperitoneal fibromatosis is exceptional as a neonatal tumour.