[Focal nodular hyperplasia of the liver].

Focal nodular hyperplasia (FNH) of the liver is an uncommon benign lesion that usually occurs in young or middle-aged women. Although it has been associated with oral contraceptive use, no evidence supports this hypothesis. Most patients with this lesion are asymptomatic. We report the case of a 10-year-old boy with a history of transient epigastric abdominal pain over several days. Physical examination revealed a tender mass in the upper left quadrant. Abdominal ultrasonography revealed an 85 3 45 mm mass located in the left lobe of the liver. Computed tomography-guided biopsy showed histological changes consistent with FNH. Left hepatectomy was performed and the diagnosis was confirmed by histological study. FNH of the liver is extremely rare in children, especially in boys. Unlike adenoma, malignant transformation of FNH has not been described and consequently patients can be periodically followed-up with imaging tests, without need of surgery. The differential diagnosis includes other benign hepatic lesions such as hemangioma and hepatocellular adenoma. Surgical resection is indicated in symptomatic patients, usually with abdominal pain, cholestasis or palpable abdominal mass, and when the differential diagnosis, especially with hepatic adenoma, is unclear.