Progressive type of focal nodular hyperplasia characterized by multiple tumors and recurrence

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."