Purpose: Although recent advances in diagnostic imaging have allowed a number of patients with focal nodular hyperplasia (FNH) to avoid surgical treatment, the natural course of large FNH is still unknown.
Case report: A 25-year-old man was admitted because of a large hepatic mass detected on routine examination in June 1998. The only laboratory abnormality was an elevated gamma-GTP. Computed tomography, angiography, positron emission tomography using F-18 fluorodeoxyglucose (FDG-PET), and scintigraphy using technetium-99m-galactosylneoglycoalbumin(99mTc-NGA) demonstrated a spoke-wheel appearance of vessels, normal hepatocytes, and no malignancy. Histologic findings on needle biopsy were consistent with FNH. After informed consent, the patient agreed to observation. Two years after the initial diagnosis, he has no symptoms, and there are no changes in the size or character of the lesion on computed tomography.
Discussion: Careful observation of patients with FNH is required because its natural course is unknown and these lesions can bleed or rupture.