Focal nodular hyperplasia (FNH) is usually a stable lesion that does not enlarge when studied for long periods of time; recurrence after resection has not been reported. We present a patient with a solitary FNH lesion that enlarged, was resected, and then recurred. A second resection was performed because of abdominal pain and disclosed multiple lesions, two of which were acutely infarcted. Thirty-two months later there was ultrasound evidence of further recurrence. Histology of the lesions showed the usual appearance of FNH with ducts and ductules in the central stalk regions but also some areas with minimal ductular differentiation and scanty connective tissue. Because of the clinical and histological appearance, the lesions in this patient were distinct from the usual type of FNH and merit the name "focal nodular hyperplasia, progressive type." (โฌ&PATOLOGY 1995; 21~970-975.)
The majority of patients with focal nodular hyperplasia (FNH) have one or a few lesions that are asymptomatic and are discovered incidentally during imaging studies, abdominal surgery, or autopsy.'-g We report a patient with a large FNH lesion that grew over a period of months, was resected, and recurred with multiple lesions several years later. To our knowledge this is the first case to be reported of FNH recurring after resection. Because of the unusual clinical behavior, we believe this lesion is distinct from the usual form of FNH and merits the distinct name of "focal nodular hyperplasia, progressive type."
It has been hypothesized that FNH is a secondary hepatocellular response to the hyperperfusion provided by a primary arterial malformation. The presence of abundant adjacent tissue containing early transition lesions allows evaluation of this hypothesis. Morphometric data on this adjacent tissue suggests there is a Abbreviation: FNH, focal nodular hyperplasia.