Ectopic pregnancy with undetectable serum and urine beta-hCG levels and detection of beta-hCG in the ectopic trophoblast by immunocytochemical evaluation.

BACKGROUND

Ectopic pregnancies associated with negative urine or serum pregnancy test by radioimmunoassay usually demonstrate either nonviable trophoblast or absent production of beta-hCG by the ectopic pregnancy.

CASE

We report a patient with intra-abdominal hemorrhage caused by a ruptured ampullary ectopic pregnancy who had undetectable serum and urine beta-hCG levels (less than 5 mIU/mL). Immunoperoxidase staining of the ectopic trophoblastic tissue obtained at surgery revealed both beta-hCG and placental alkaline phosphatase.

CONCLUSION

Negative serum and urine pregnancy tests can occur even though beta-hCG produced by the viable ectopic trophoblastic tissue can be demonstrated by immunoperoxidase staining.