The clinical, radiologic, and pathologic characterization of benign hepatic neoplasms. Alleged association with oral contraceptives.

Poor histopathologic documentation and confusing terminology have caused focal nodular hyperplasia (FNH) and liver cell adenoma (LCA) to be categorized together as "benign hepatomas." FNH and LCA are distinguishable grossly, microscopically, and ultrastructurally. In a majority of instances they may be differentiated by combined angiography and liver scan: FNH is hypervascular and exhibits normal uptake on scan whereas LCA is hypovascular and cold on scan. FNH almost always follows a benign course, rarely undergoing hemorrhagic necrosis and rupture. FNH does not possess malignant potential; the prognosis, even if unexcised, is excellent. Resection is indicated only if FNH is symptomatic. LCA often ruptures and its malignant potential remains uncertain; the prognosis is guarded and resection is indicated. The literature reported association between FNH and oral contraceptives is anecdotal. However, the recent marked increase in the incidence of LCA's, their almost exclusive occurrence in young women, and the consistent hormonal history strongly suggests an association between oral contraceptive use and LCA's, although here too, statistical evidence is lacking. Prognostic and therapeutic considerations mandate that a clear distinction be made between FNH and LCA.