Focal nodular hyperplasia of the liver and oral contraceptives.

The increased incidence of liver tumors in women of childbearing age who have been using oral contraceptives for many years suggests an environmental causation. The causative agent may be the steroidal oral contraceptives. Two lesions are recognized: focal nodular hyperplasia and hepatic adenoma. This paper concentrates on focal nodular hyperplasia, with two cases added to the four previously described cases. It is postulated that the estrogen component causes vascular lesions characterized by myointimal hyperplasia and thrombosis, leading to infarct, necrosis, and subsequent nodular hepatic regeneration. The clinical feature highlighted is the long history of gastrointestinal disturbance associated with negative gastrointestinal investigation with the possible exception of cholelithiasis. It is suggested that gray-scale ultrasonography is an effective screening method that also aids in a definitive diagnosis. As these tumors are often incidental findings it is emphasized that the liver should always be inspected at laparoscopy. Ultimately, diagnosis by biopsy or excision is essential as it may well be possible to treat cases of focal nodular hyperplasia of the liver conservatively, once oral contraceptives have been discontinued.