Oral contraceptives, pregnancy, and focal nodular hyperplasia of the liver.

There is uncertainty regarding the role, if any, of oral contraceptive steroids in the development of focal nodular hyperplasia of the liver. In a 36-year-old woman, a large left hepatic lobe tumor developed that was detected after 11 years of using these drugs. The tumor regressed when administration of the drug was stopped but began to increase in size during a subsequent pregnancy. A left hepatic lobectomy during the second trimester disclosed focal nodular hyperplasia. Both contraceptive steroids and pregnancy, with high levels of endogenous sex steroids, favored tumor growth in this patient, suggesting that focal nodular hyperplasia can be steroid related.