Estrogen-Driven Growth of Focal Nodular Hyperplasia: Truth or Myth?

The etiologic association between focal nodular hyperplasia (FNH) and estrogen has been a subject of doubt and controversy. We present a case of a female patient with FNH that had been monitored for several years with noted size stability and later regression, who developed tumor growth during pregnancy. This case suggests that a subset of FNH is indeed hormone sensitive, as opposed to what has been frequently suggested by many other reports that question the association, a finding that may have clinical implications, in terms of monitoring of patients with high estrogen statuses.