Don't ignore a positive pregnancy test.

Case reports are presented on 2 patients to show the importance of following up apparently false positive results of pregnancy tests. In case 1, a 25-year-old woman was admitted to the hospital with severe breathlessness in September 1987. After she had stopped using oral contraceptives (OCs) in 1985 her periods were irregular and on 4 occasions the results of pregnancy tests bought over the counter were positive. She was twice referred for ultrasound examinations, but the uterus was empty each time. In April 1987, dysfunctional uterine bleeding was diagnosed; she was treated with clomiphene. She then experienced intermittent pleuritic chest pain and breathlessness on exertion. In early September she was admitted with acute breathlessness and chest pain. A further pregnancy test was positive; results of laparoscopy of the pelvis were normal. A radioisotope ventilation-perfusion lung scan showed multiple filling defects in the left lung and no perfusion to the right. A presumptive diagnosis of choriocarcinoma was made with the syndrome of tumor growing in the pulmonary arteries. In case 2, a 32-year-old woman was admitted to the hospital in March 1988 with acute lower abdominal pain. A pregnancy test was positive, and she underwent laparoscopy for suspected ectopic pregnancy. A macroscopic tumor was found on the surface of the right ovary and a right salpingo-oophorectomy was performed. A subsequent histological examination showed choriocarcinoma. The 2 cases reported show the importance of seeking a definitive explanation for a false positive result of a pregnancy test. If the test has been performed correctly and proteinuria and drug interference, for instance, are ruled out, then a raised human chorionic gonadotropin concentration, particularly in young women, is virtually certain. In most cases this will be due to a pregnancy that ends in a 1st trimester abortion, but in a small minority it will be due to the hormone producing a tumor such as choriocarcinoma.